Excellent. Make sure the copper pipe is not deformed. perfect circular run without burs. file it, sand cloth it. whatever it takes from your arsenal, just make sure the pipe is smooth, round and free of imperfections. The fit was snug and the included epoxy went on perfectly. Not only the adapter, but the wing tite drain, was a god send. best drain replacement for a stand up shower on a concrete slab. PERIOD. I'm typing this roughly a year after installation and my shower is still leak free. Honestly, their is no substitute. I'm a plumber and I stand by this message and this product 100%