Master Lock - (4) High Security Pro Series Keyed Alike Padlocks w/8 Keys, 6230NKA-4 w/BumpStop Technology

I am not a lock expert or even a lock enthusiast, but I am involved in the metal machining business and the excellent manufacturing standards that this lock is made to is outstanding - The lock was a bit rough in its movement when it first came out of the box but a generous dose of Royal Purple lubricant in every orifice made this little tough guy very smooth, very "Friendly" in it's operation - There are some tough manufacturing requirements in this lock and Master really nailed it - The materials are well chosen for the application as well - Also - Master made it easy to get spare keys so that is an extra reason to love this sweet little guy - Awesome lock Master Lock!!

Excellent quality, very sturdy exactly as described

Great Locks! I leave them out in the rain and snow, and they always work. Get as many as you can with the same key, so you don't have to carry a big wad of keys around.

Great locks

Definitely withstood someone who was trying to break into my storage. The boron alloy is no joke and proven to be difficult to get though. They were almost successful but at the end of the day. The lock did its job.

Very stout, 'bumping' resistant, re-keyable. A real workhorse that should last for decades. Fairly expensive, maybe more so than they should be, but at least the quality seems to be first rate. The shackles are not spring loaded, so two hands are often needed to manipulate them, it's an annoyance under some circumstances. No padded band on the outside, it can scratch or dent whatever it's securing.

great quality, thank you

I have a beach house in Baja which is in a remote area and completely off-grid. I've used a number of different types of locks over the years to secure the house while I'm gone, but have experienced 2 break-ins nonetheless...until using these locks. These locks are virtually bullet proof. As mentioned above, I've had no break-ins since using these locks. They also hold up well to the marine environment. Keep in mind, though, nothing metallic will hold up indefinitely to the salt air right on the beach. I replace mine as corrosion becomes evident, which is every year and a half or so. That being said, it's the very best lock I've found for my needs. To top it off, customer service is excellent and timely. This is a great product sold by a great company!

Heavy duty quality lock.