Good eye-hand coordination is required to insert the buckle. To tension the parts once inserted, a sub termino-lateral grip is used.
The palm face of the thumb’s pukp rests on the outer face of the first phalanx on the index finger. The muscles that stabilise the grip are the first dorsal interosseous, that acts on the index finger, the short flexor, the first palm interosseous and abductor of the thumb.

This aid has a clip belt buckle on the one side that can be altered in length, and an end complete with zip that can be opened.

The clip belt buckle also requires good coordination and significant force has to be applied by the thumb, opposing the index finger to clip the fixing device in place.