Straight Drains—Straight drains don’t require any caulk. Fit them over iron or plastic drain pipes—their gasket will seal the drain to your drain pipe. Tighten the nut to secure the drain to the floor of your shower.

Offset Drains—Offset drains give you 3/4" of wiggle room to shift the position of your drain, so they’re handy when a floor joist is in the way. The top of the drain threads into the bottom to sandwich the shower floor without requiring a nut. Attach them to your drain pipe with plastic primer and cement, otherwise known as solvent weld.