SLAB GATE VALVE NON RISING STEM SLAB GATE VALVE NON RISING STEM The Non-rising stem slab gate valves manufactured by our company. are available in temperature classes L, P, R, S, T, and U specified in API 6A.Gate valves to be used in the 350 or 650 high temperature can be supplied on request. Gate valves manufactured by our company are available in 3000psi, 5000psi and 10000psi working pressure, nominal size from 1-13/16" through 4-1/16", material classes from AA through FF, product specification levels (PSL) from 1 through 3 and performance requirement (PR) 1.