For use with Pen No. 0303. Includes 2 cups completely assembled with tubing. Must have pressure reducing Valve No. 4020. Not included. The drink Cup Kits are complete except for the No. 4020 Pressure Reducing Valve, which must be purchased separately. The pressure Reducing Valve can handle up to 210 Drink Cups. (Several Kits) Drink cup kits are mounted on back of pen above trough, permitting trough to be used for feed.