The plastic buckle set comes in 2 parts, the buckle itself (the thing you clip open and close) and a slip lock (the thing you run the strap through).

These buckles are designed to fit with a compression strap of width of 3cm.

*We sell the strap of this width

$0.50 per set if you buy anything else on nalno.com. One set of buckle and slip lock comes free with purchase of strap