I installed a set of Hansgrohe wall mounted faucets today. It came with a crosscut nipple for the water supply. It doesn't thread like a regular nipple, it's got a lot of bite when you thread it in. Nowhere in the instructions did it mention teflon or thread sealant, and it's my first experience with this nipple. To be safe, I put some pipe dope on the threads, I haven't yet turned the water on, that will be tomorrow. If this leaks in the wall, I will have no way of knowing until it comes through the ceiling downstairs. Is teflon required on these nipples? From what I can tell, Teflon would be very restrictive.