Master Lock - Four (4) High Security Pro Series Padlocks 6321NKA-4 w/ BumpStop Technology. This listing is for four (4) High Security Keyed Alike Padlocks w/ 8 keys. ProSeries Padlocks are designed for Commercial/Industrial applications. Limited Life Time Warranty. If you order two 4-packs they will NOT necessarily be keyed the same. To buy multiple 4-packs keyed alike you need to purchase the locks via fulfilled by MERCHANT - HOW TO FIND: When you look at the listing there is a link showing the Other Sellers on Amazon. This is under the "add to cart button". Look for the 4-pack fulfilled by Merchant LocksChocksTiedowns. If you purchase any 4-pack multiple we will automatically key all locks the same. These locks feature the BumpStop Advanced Cylinder Technology. (for explanation see more product details below). DIMENSIONS: 2-1/8 (54mm) wide heavy steel body, each weighing 1.55 lbs. A 5/16 (8mm) diameter hardened boron alloy shackle with 3/4 (19mm) inside height clearance. Solid iron shackle shroud resists harsh physical attacks. The removable cylinder can be replaced or re-pinned. 5 spool pin tumbler cylinder for added pick resistance. Dual ball bearing locking mechanism resists pulling and prying.