Connect Accumulator Tank to outlet side of water pump for best results, Accumulator tanks hold a reservoir of air and water down from the pump. Internal rubber membrane eliminates maintenance and simply fitted to new or existing . pump life, lower battery drain,reducing noise and providing a more water supply. Accumulators allow the pump to reach shut-off pressure more smoothly which reduces the on/off which gives better control of hot water delivery. Applications:Boat,Marine, RV,, Inlet/Outlet Dia:1/2Inch MNPT Volume:0.75 Liter(25 FL OZ) Water psi:Max 125 PSI (8.6 BAR) Pre-charge pressure:10 PSI(0.87 BAR) Air Fill Vale:standard automotive style tire valve. Note: 1.Relieve air psi prior to disassembly 2.Do not use to pump fluids,gasoline, fuel oil. 3.Do not use pump in a environment or use where vapors are . 4.Petrol or fluids with flash point 37C(98F), explosion or death may occur. 5.The accumulator tank comes pre-pressurized at 10 PSI. For optimal usage, set accumulator tank to -3 PSI your water pump's cut-in pressure and make it is connected to the outlet of the pump 6.Do not over pressurize tank. Pressures over 125PSI(8.6BAR) may rupture tank and cause personal injury. Suitable for:Marine RV Boat Colour:Black Material:ABS Package Contents: 1 * Pressure Tank Water Pump Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.