Omnium Replacement Seatpost Clamp

Here's what Omnium has to say:

Omnium seat clamps, for keeping your seat post right where you want it!

Aluminium clamp, stainless steel 5mm hex bolt.

Size Guide

34.0mm =  For all steel cargo bikes with 31.6mm seatpost tube (except CXC V3)

34.9mm = For all titanium bikes

29.8mm = For older cargo bikes with 27.2mm seatpost