The Schedule 40 PVC Reducer Bushings are great for reducing/enlarging the tubing or pipe size. These fittings have a Spigot (SPG) fitting on one end and a Slip fitting on the other. Reducing the tubing size will increase the amount of head pressure the pump will have to overcome. A spigot end is the same outer diameter as the tubing or pipe. It will need to be attached with a slip fitting.