The basic design, made of hardened steel of circular cross section bent into a U-shape with a removable crossbar, has been emulated by numerous other manufacturers, and adapted with variations in size and shape for other applications, such as locking motorcycles.

[4] Kaplan partnered with Michael Zane, whose father had a metal manufacturing company, to produce and market the locks.

Indeed, local hardware stores would often sell inexpensive chain cut to length using simple bolt cutters.

The first Kryptonite lock model was made of sheet metal cut and bent to shape, but the company soon went to the now universal circular cross section.

[10] After this problem became public, Kryptonite offered a free exchange program for all owners of locks with tubular mechanisms.