Neptune Systems DOS Replacement Pump HeadDirect replacement fluid metering head assembly for the Neptune DS Dosing Pump. The easy to install head replaces the tubing, roller, and plastic housing head cap. Compatible with DS and DS QuietDrive I nstalls in minutes Replaces wearable tubing The Neptune DS Replacement Head assembly comes with everything to replace the current fluid metering head on your DS system. Over time, the self lubricating tubing will start to age, and can also cause excess