- Produced for egg hen. Made of special hard plastic, all internal parts are 304 quality stainless steel. It only works up and down. It has 10 mm keyway. 8.8 mm holes should be drilled. The thread should not be opened at the place to attach, the nipple is to be threaded automatically with the special conical screw. 0.70 - 0.80 ml / min. can give water.