"Alligator clips" are made in various sizes--but four cover most belts in common use (each strip is 11-inch (280 mm) long).

No. 15 for belts 1/8" to 5/42" (3 to 4 mm)
No. 20 for belts 5/32" to 3/16" (4 to 5 mm)
No. 25 for belts 3/16" to 7/32"
No. 35 for belts 9/32" to 5/16" (7 to 8 mm)

A length of clip is hammered in at each end of the belt and joined with two sections of the special oval pin supplied  - these being designed to work back-to-back. Alternatively, a length of nylon or red-fibre rod can be used.
An instruction sheet, reproduced below, is supplied with each clip.

Clips can be ordered online here, or by phoning: 01298-871633 six days 09:00 to 23:00
Details of the flat, round, link, Poly-V, miniature and standard V-belts we supply can be found here and many of them ordered online here for immediate delivery. Should you have a question about machine-tool drives of any kind, you are welcome to contact by phone for advice.