【Easy to install】:The Cartridge Valve is same with the WS08W-01T-C-N-0 Replacement,and you also need Tool Needed:7/8" Wrench or an allen wrench that has a short end onit to dismantle and install Cartridge Valve of RV 【Package】:Including plastic retentionnut,black o-ring and the set screw 【OE Number】:WS08W-01T-C-N-0；177094；WS08W01TCN0 【Advantage of the set screw】:The set screw has manual override capabilities,it can be used in the event of a power failure 【Advantage of the o-ring】:The Cartridge Valve have four black o-rings to provide a good seal