Parveen Standing Valves and Companion Seating Nipples are normally used in intermitting or chamber lift wells in the bottom of the tubing or chamber. The seating nipple is an integral part of the tubing string. The standing valve seats on the NO-GO of the seating nipples and seals in the honed bore of the nipple to prevent the fluid from flowing back into well bore when high pressure gas is injected under a slug of fluid. Parveen manu-factures E-3 type of standing valve, in all popular sizes. A complete line of seating nipples are available to accept the standing valves.