OnGuard Mastiff 3.5 ft Chain Lock with Integrated Key Lock – 10 mm Hardened Steel Hex Links (110 cm / 3.57 ft) – X2P Double Bolt Lock Head, Z-Cylinder Core, 5 Keys

We bought this to lock down our Ebikes at campsites when we are not around and/or inside our RV. It's so very strong we feel quite comfortable leaving our Ebikes locked with this. We remove the batteries and keys, lock them up and no worries! Great value, compatible with our Ebikes, easy to use although quite heavy. It appears as sturdy as it is, so it's a good theft deterent.

This lock is no joke. The chain is heavy and there is no denying that. The lock is a bit silly in my opinion. The key doesn’t easily slide in and it’s very ambiguous as to whether it’s locked or not (click feel when turning key). The key doesn’t come out when it’s unlocked - which is very clear - but I would rather have a more traditional @click - it’s locked” type of feel.

The 10mm chain is substantial. The padlock size took me aback when I first unwrapped it. The lock mechanism is smooth and easy to use. I like that the lock has a rubber coating on the U portion. I was somewhat surprised by the amount of plastic sheathing on the lock, but it does appear sturdy. I bought an OKC noose chain to go with (my Scouting unit often goes on group rides to the movies, etc., so this extends the group coverage while we're inside). The OKC links are narrower, but do slide over the lock (displacing some of the rubber coating). The OnGuard chain is robust. I could slide the nice cover enough to check all the link welds which looked good. Hoping to get many an event-free year with this lock and chain. Nothing will deter a determined thief, but this will at least divert attention elsewhere. When we go away, the lock and chains are used to secure our bikes to the floor anchor.

A touch heavy, still a great lock. LOVE the extra length. I carry mine in a basket so the weight does not bother me.

This thing is a BEAST. Nicely manufactured and very high quality. The protective sleeve over the chain is a nice touch, as it prevents scratching of your wheels. I also like the key mechanism, which is well protected and works very smoothly. My ONLY complaint... and it's obvious... is the weight of this thing. Its heavy to the point where I HAVE to wear a back back to carry it around. You're definitely not going to wrap this around your frame or something when you're riding. And I'm on a 125cc motor-scooter. Either way, it's gonna take some work for someone to cut through this thing.

I struggled to figure out how to use this the first time, because I thought there was a trick to turning the lock and removing the key. There’s no trick. Basically if the key is in the lock the lock opens. You can’t remove the key unless you lock it again. This is a rather genius way of making sure you don’t lose your key. Now that I understand it, it’s super simple to tie my bike up anywhere in just a few seconds. The chain is heavy duty, so this is not a fun thing to carry around (heavy). I keep it in a pannier on my bike, so it never really bothers me. Another option is to wrap it around the top tube several times and lock it in place while on the go. No need to keep it in a backpack. I got the smaller size, and that's more than enough length for securing my bike everywhere I go (unless you are tying it to a tree). It's a rather menacing looking lock, so unless someone is traveling with a saw, your bike isn't likely to become a target. I was tempted to buy some of the cheaper options, but I am SO SO glad I went with this one. I feel very confident about my bike being secure wherever I leave it. Definitely worth the money. Two year update: I've taken this with me to different states and countries and used it with different bikes I have purchased in different places. Its been rained on, dragged, packed in luggage, left in a shed, and I've never has issues with it, and no one has ever attempted to steal my bikes. I've oiled the lock like three times in two years. Its a winner.

Like carrying a tow chain. I will only use this when my bike needs to be left outdoors. Not something you’ll carry on a ride. But, it’s what I expected and definitely serves its purpose. Don’t buy it if you are expecting it to be light.

Awesome chain. It will delay potential bike thieves much longer than most cables/wires that are on the market. Its heavy fabric outer covering protects my car's roof from scratching. It comes with 4 keys, too, unlike some other famous companies that give you 2 keys, and then charge exorbitant fees for additional keys/lock heads. (Yakima can you read this please.) I have a 2-bike roof rack system, and I will buy a 2nd Mastiff to protect another bicycle. The chain is very heavy and not long enough to securely protect 2 bikes, however, it will secure 1 bike.

El candado se ve de una gran calidad, es pesado pero no más más otras marcas con el mismo nivel de seguridad. Hasta el momento me siento seguro con est candado, llego antes de lo esperado.

Great lock, very sturdy. The locking mechanism wouldn't work properly after a year, at first I thought the lock was defective but it just needed to be lubricated (either WD40 or White Lithium grease, whatever you have will fix the issue will work). So to anyone looking for a sturdy lock you wont regret this one...just keep it lubricated at least once every few months, or once a month would be better especially if you use the lock out doors often.

Llegó en tiempo y forma, con todos sus instructivos y garantía de autenticidad del producto. Es muy pesado y seguro.

5/5 For sure. A thief got into my apartment building bike locker room: several nice bikes were stolen. My bike is in a cage, the door was mangled and my "shroud" padlock removed, but this hardcore chain lock held up on my bike inside. I can see the thief went to work on it, the chain and u-lock keyhole are both damaged but intact. I'm very pleased with this lock.

Realmente muy resistente, lo que lo hace impresxindible para proteger bicicletas.