Eight (8) High Security Locks Keyed Alike w/ 16 Keys. ProSeries hardened solid steel body padlocks are designed for Commercial/Industrial applications. These locks feature the BumpStop Advanced Cylinder Technology. (for explanation see more product details below). The same lock with a shorter shackle is also available, search 6230NKA. ATTENTION: If you order two 8-packs or any multiple of this lock they will NOT automatically be keyed the same. To receive 16 keyed alike you will need to order direct from the merchant LocksChocksTiedowns also available here on Amazon. APPLICATIONS: Industrial and manufacturing environments. it's a popular lock used by business owners to secure their storefronts and business gates. With Marine recreation uses, they will withstand the harsh elements. Utility meters, substations and cable boxes to name a few others. DIMENSIONS: 2-1/2" (64mm) wide round solid steel body, each weighing 1.68 lbs. A 7/16" (11mm) diameter hardened boron alloy shackle with 2" (51 mm) inside height clearance. CHROME rustproofing provides longer life. These high security, rekeyable 5-pin cylinders with spool pins are virtually impossible to pick. And a dual ball bearing locking mechanism resists pulling and prying. FEATURING BumpStop TECHNOLOGY - Lock bumping - a surprisingly simple method of breaking in through locked doors and padlocks - is undoubtedly the newest emerging threat to personal property security. And virtually all locks in use today are particularly vulnerable to bumping. Until now. BumpStop Advanced Cylinder Technology employs an innovative, patent pending design which utilizes a unique reverse rake tapered driver pin, high performance springs and tightly machined cylinder chambers. During a bump attempt, this design prevents the transfer of force from the bump key to the pins and therefore blocks rotation of the cylinder so that the lock remains locked.