I'm pretty sure it's 1-1/4" coil hose. On Mon, Jun 20, 2022 at 9:36 AM Olivier Hecht <oehecht at gmail.com> wrote: > Hi all. I’m away from my boat but need to order the drain hose from the > rear of the cockpit seats to the transom. Does anyone happen to know the ID > I need? Thanks in advance. >