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On-Guard Mastiff Keyed Chain Lock

4.4 4.4 out of 5 stars 728 ratings

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Keyed Shackle Lock
Brand Onguard
Lock Type U-lock
Item Dimensions LxWxH 4.33 x 9.06 x 1.57 inches
Material Hardened Steel shackle
Style Keyed Shackle Lock

About this item

  • Steel/Vinyl
  • U-Locks

From the manufacturer

ABOUT US

On the inside, OnGuard locks comes with double and quad-locking mechanisms, bump-resistant cylinders, and hardened steel shackles and chains. On the outside, our locks are fully-coated to protect your bicycle or powersport vehicle from scratches and to shield internal parts from the elements, while the bright color scheme sends a clear warning to thieves: don’t even try! And then there’s the extras: all-tube mounting brackets, five laser cut keys, key-code registration, comprehensive anti-theft programs.

Product Description

The superior protection of our X4P locking mechanism mated to a standard length 230mm 9.06'' 14mm 0.55'' TriRadius hardened steel shackle for more locking options.

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Customer reviews

4.4 out of 5 stars
4.4 out of 5
728 global ratings

Customers say

Customers like the quality, sturdiness, and value of the outdoor recreation product. For example, they mention that it's easy to lock and unlock, has a semi-hard, black plastic layer over the metal bar, and that it definitely won't be easy to crack. That said, opinions are mixed on the size, weight, and mounting.

AI-generated from the text of customer reviews

77 customers mention58 positive19 negative

Customers like the quality of the lock. They say it's a solid lock, with tight tolerances and it works flawlessly. They also say it is a heavy lock, well made, and durable. Customers also say that it is capable of keeping thieves from cutting it.

"...Easier to use than those circle-wound cable locks, and quite a bit more secure...." Read more

"...through so for the money spent i think it is great value on a fairly heavy duty lock, I would buy again at this point." Read more

"...That being said however, this U-Lock is sturdy and definitely won't be easy to crack...." Read more

"...The lock held up really well. I do not recommend ever leaving a bike parked overnight in NYC unless the bike is worth $75...." Read more

68 customers mention51 positive17 negative

Customers like the sturdiness of the lock. They say it has a semi-hard, black plastic layer over the metal bar. The key mechanism is solid and operates smoothly. The lock is good quality and definitely won't be easy to crack. The shackle is thick and the steel is very strong.

"...Comes with a mounting clip that is screw on, not flimsy like the others that have a pull-tight mount...." Read more

"...It seems very thick and should take someone a bit of time to try and hack through so for the money spent i think it is great value on a fairly heavy..." Read more

"...This lock has a solid tumbler & shackle that operate cleanly. And when it gums up I just squirt some WD40 (as suggested by the owners manual)...." Read more

"Bike attachment crews seem prone to stripping so be careful and concise with your tools, just use a screwdriver anyways so you don't crack the..." Read more

29 customers mention26 positive3 negative

Customers like the value of the lock. They say it works great for the price, is reasonable, and a great buy. Some say that it works as well as a good bludgeon as s a lock, and is satisfying. Overall, customers find the product to be useful and reiable.

"...Great value for the price, I'd recommend this lock to any bike owner." Read more

"...time to try and hack through so for the money spent i think it is great value on a fairly heavy duty lock, I would buy again at this point." Read more

"...This lock has a solid tumbler & shackle that operate cleanly. And when it gums up I just squirt some WD40 (as suggested by the owners manual)...." Read more

"Very hefty, solid lock. It looks quite nice too...." Read more

13 customers mention13 positive0 negative

Customers find the keys in the outdoor recreation product easy to use and bring several extra keys along with a bracket to install on bike. They also mention that the keyhole is recessed and appears well protected from anything but a key.

"...Comes with 5 keys (1 big, 4 small) which is nice but unnecessary for my use...." Read more

"...Moreover, each lock includes 5 spare keys and a tag to allow you order replacements. You can tell these guys know their stuff." Read more

"...Pros: Heavy duty, bike mount, several keys, large frame for bigger poles..." Read more

"...It comes with lots of keys which is nice...." Read more

12 customers mention12 positive0 negative

Customers find the lock very easy to use and secure. They say it's easy to set up, carry, and install. Customers also say that the key version is convenient to use, and the security level is higher.

"...Attachment is really easy to use, the design of it is smart. Gripes are minor." Read more

"...lock, oh they are laser cut so they are pretty nifty looking and harder to pick...." Read more

"I have peace of mind with this lock. It is easy to use and the mounting bracket allows me to easily take it wherever I go...." Read more

"...The key version is so convenient to use and the security level is higher." Read more

31 customers mention18 positive13 negative

Customers are mixed about the size of the lock. Some mention it's big, but with the clip on it goes easily on the bike. They say the lock has plenty of length and width, and is good size for the GTS300. However, others say that its needlessly odd shape and overly large size made it difficult and even too big for their M365 scooter.

"Great lock, easy to lock and unlock. It is big and fairly long however it just missed being able to get my front tire and frame (24 inch) together..." Read more

"This thing is quite large and as another reviewer has mentioned, comes in toy truck colors...." Read more

"...the u-bar itself wouldn't be, but it does seem to have a superior width and weight. Attachment is really easy to use, the design of it is smart...." Read more

"...The size is perfect for going through the frame and wheel of the bike and around a signpost. Not much wiggle room left after that...." Read more

27 customers mention14 positive13 negative

Customers are mixed about the weight of the bike lock. Some mention it's sturdy and quite heavy, while others say it doesn't add much weight to the bike. Some say it'll work well and is portable, while still being reliable. However, some customers feel the weight is awkwardly weighted.

"Heavy - works as well as a good bludgeon as a lock..." Read more

"...Cons: Heavy, no selection of colors, bike mount could be better, price" Read more

"...i went with this U lock and it does the trick, feels secure and easy to travel with." Read more

"...The only real cons I have with it are the awkward and bulky style of the actual lock part of the the design, although rarely, its needlessly odd..." Read more

19 customers mention12 positive7 negative

Customers are mixed about the mounting of the bike lock. Some mention that it's heavy duty, convenient, and easy to use. However, others say that the mounting bracket broke after a few months of use, the screws were all busted, and the mounting part on the lock twists.

"...Comes with a mounting clip that is screw on, not flimsy like the others that have a pull-tight mount...." Read more

"After 6 months of daily use, the mount first broke in the front, making the lock very loose and wiggly, and then in the back, making it impossible..." Read more

"...One amazing reason to get this lock in particular? It comes with a mount for the lock...." Read more

"...First is the on-bike clip is comes with, most u-locks use a slide into place clip, this one used a sort of side clip that I find vastly superior the..." Read more

Very Secure Lock.
5 Stars
Very Secure Lock.
A very good lock. It's kind of big but would be very hard to break. Didn't like bracket that came with lock so I just put around seat post and rear carrier.
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Top reviews from the United States

Reviewed in the United States on September 27, 2012
Size: 4.53 x 9.06 - InchStyle: Keyed Shackle LockVerified Purchase
5 people found this helpful
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Reviewed in the United States on August 25, 2017
Size: 4.53 x 9.06 - InchStyle: Keyed Shackle LockVerified Purchase
2 people found this helpful
Report
Reviewed in the United States on December 23, 2013
Size: 4.53 x 9.06 - InchStyle: Keyed Shackle LockVerified Purchase
One person found this helpful
Report
Reviewed in the United States on August 13, 2015
Size: 4.53 x 9.06 - InchStyle: Keyed Shackle LockVerified Purchase
Reviewed in the United States on June 6, 2013
Size: 4.53 x 9.06 - InchStyle: Keyed Shackle LockVerified Purchase
Reviewed in the United States on December 15, 2015
Size: 4.53 x 9.06 - InchStyle: Keyed Shackle LockVerified Purchase
35 people found this helpful
Report

Top reviews from other countries

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KAISO
5.0 out of 5 stars O cadeado que tanka o Brasil
Reviewed in Brazil on July 31, 2023
Size: 11.5 x 29.2 cmStyle: Keyed Shackle LockVerified Purchase
7 people found this helpful
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Alejandro D.
5.0 out of 5 stars Seguridad/precio
Reviewed in Spain on November 8, 2022
Size: 4.53 x 9.06 - InchStyle: Keyed Shackle LockVerified Purchase
Flo
5.0 out of 5 stars Fait le job
Reviewed in France on August 31, 2022
Size: 4.53 x 9.06 - InchStyle: Keyed Shackle LockVerified Purchase
zaboo
5.0 out of 5 stars Excelente U-Lock Seguridad 8/10
Reviewed in Mexico on July 12, 2020
Size: 4.53 x 9.06 - InchStyle: Keyed Shackle LockVerified Purchase
6 people found this helpful
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Michael S.
5.0 out of 5 stars Decent and easy to use, would recommend it
Reviewed in Canada on January 22, 2019
Size: 4.53 x 9.06 - InchStyle: Keyed Shackle LockVerified Purchase
5 people found this helpful
Report