I actually bought these elsewhere but before TSC started selling them. I've done a bunch of research. These are great on the bottom of pop bottles, water/milk jugs, or 5 gallon buckets. On thin plastic a 5/16 drill bit will work fine. On the 5 gallon buckets, you'll need the 11/32 drill bit. These are for vertical installation only - so either prop up your bucket on cinderblocks or hang them. If you want horizontal nipples, you're going to have to ebay them - the only supplier in the states that I can find is on there. I use both the horizontal and the vertical. Both use the 11/32 drill bit for installation. Anyways, these can be used with chickens, ducks, & turkeys. These help keep our coops cleaner, the water cleaner, and makes filling the waterers much easier so they also save me time! All in all, I prefer the horizontal better, but both designs have specific uses for me that I will always keep both on hand.

Maybe I need to have a slightly larger drill bit, but 3/8 inch will not thread into PVC. I tried using a 3/8 inch screw to make treads in the PVC with no luck. The plastic threads on this product won't catch and end up getting crushed.