This is a replacement seat sleeve that must be fitted with a specific rubberised adhesive (QGLUESS) to secure it in place. 

It is therefore recommended that it is fitted by a Brompton dealer 

On bikes produced after 2002 a sleeve with an upstanding key should be used, bikes produced before this date should use a sleeve without the upstanding key.

This is a replacement seat sleeve that must be fitted with a specific rubberised adhesive (QGLUESS) to secure it in place.  It is therefore recommended that it is fitted by a Brompton dealer  On bikes produced after 2002 a sleeve with an upstanding key should be used, bikes produced before this date should use a sleeve without the upstanding key.