Includes:

25.4mm seat post clamp with 2 allen bolts, SILVER ALLOY

Application:

Use with a 25.4mm seat post.

Note:  This clamp will fit onto a bicycle frame seat post bracket (part of the frame sticking up to receive a clamp) that is 31.8mm diameter; 

after putting the seat post clamp onto the frame, then a 25.4mm seat post can be inserted into the clamp.  This is a standard size clamp for most 24" and 26" bicycle frames.