A simple bit of kit that I've used a bit to do lots of ferrying child-seat about on stuff... built up as a singlespeed it worked fine but was a stretch to small for me so I bought a larger frame.
The frame itself is probably about 16" (can't be arsed to measure it but loads of photos). Concealed headset, bottom bracket (isis, still smooth) bars, stem forks (project two type with canti studs removed).
£60 posted in UK or £50 pickup from Rossendale (16 miles north of Manchester)
It has Diamonback stickers on it but I doubt that's its origin -0 it looks quite like a Boardman frame to me - well built, some decent tubes and strengtheneing features... disc only.
It's for 26" wheels, It's for a 27.2 seatpost... erm... anything else? Please ask bikeframethingie@minnellium.com

