2 pcs Outdoor sports tools: 1 x For Brompton Seatpost Sleeve set Adapter 1 x shimFeature: for chain stay, protect more rear fork of frame. Size: thickness 1mmDuring installation, the protrusion is aligned with the groove at the back of the seat tube, and then the outer side of the reducing sleeve needs to be coated with glue.which can be fully adhered when inserted into the seat tube after 6 hours.Used for: Brompton Bikeadapter: from 34.9 to 31.8mmMaterial:plastic+carbon fibercolour:blackPackage Contents:1 x For Brompton Seatpost Sleeve set Adapter1 x shimOnly the above package content, other products are not included.Note: Light shooting and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.