HP Velotechnik Seat Rain Cover 12 speed We would use DIN 912

We would use DIN 912 M6 x 22mm A2

as found on Catrikes

For ICE Trikes with Rear Suspension that were manufactured prior to 7/2015

strong and durable

6mm hex keys

HP Velotechnik Seat Rain Cover 12 speed We would use DIN 912Made of durable ripstop nylon, the light cover keeps the recumbents seat dry and clean when parked. When not in use, it is kept in the integrated zip bag on the ErgoMesh seat or, for cyclists with a BodyLink hardshell seat, in HP Velotechniks new optional Microbag. If you have a BodyLink seat, the Microbag has a Velcro strip that the rain cover attaches to. Otherwise, you will need to put the included Velcro strip on your seat back to secure the rain