Aluminium shim for reducing the seat tube for smaller seat posts.

27.2mm -> 25.4mm to convert Kris Holm and ONZA unicycles for  25.4mm seat posts.

29.2mm -> 25.4mm to convert Koxx-One unicycles for 25.4mm seat posts.

25.4mm -> 22.2mm to convert frames with 25.4mm seat tube (Insidediameter) for 22.2mm Miyata seat posts.