Posted on July 20, 2022 by Jack Hydraulic Proportional – Additional Spool Types W6-spool: improved W-spool – crossover all ports are closed (to stop) – then decompress at center, open 2% A to T and B to T W8-spool: improved W1-spool, like W6 but 2:1 flow area Q2-spool: for injection molding cylinders