(Available Options are 5 pack, 10 pack, 12 pack, and 20 pack) Hardware kit for automatic cup style drinkers or poultry nipples. Nuts O-rings, & washers (cups or nipples not included, this is the hardware kit only). The purpose of the nut, O-ring, and washer is for connecting cups or poultry nipples to thin wall plastics. If the item, you're attaching the cup to is thin plastic and cannot make a few threads to attach cup, then this is the solution you need. This hardware kit is for mounting the drinker directly to your waterer, whether it be a bucket, pail, large pipe etc. Simply drill a 3/8" hole into your bucket, thread on your drinker and install hardware on rear. Again, cups not included this is the hardware kit only!