This is the 5/16 inch Sealtite Conduit # A-4113-0306. It is 1 meter long and includes one fitting.

Used with OMM-2, OMI-2, OMI-2T, RMP40, RMP60, RMP600, RTS, RLP40, and RMP40M; as well as parts that are used with OMM-2. OMI-2, and OMI-2T such as OMP40, OMP400, OMP60, OTS, OLP40, and OMP40M.