Sorry Charlie,Chris has just paid for it
personally i prefer the thermoplastic shims that are now available from use for about £7 ,because its plastic you done have to use grease and theres no possibility of the seatpost binding
I wouildnt have one of those no,but take heart,they do make such a thing
Many LBs's will have them,but stick a note in 'wanted' section and you're sure to find one.
Modern front mechs come with shims to go from 34.9->31.4->28.6
One size fits all it seems these days