Stubborn Delta collar stuck on shower. Was able to loosen and take it off. Found matching Delta shower cartridge and reinstalled. Healthy worried about the twisted copper lines in the shower cartridge. Tested the water we shower on for several minutes, and everything looked pretty good. Put on shower trim on and added white caulking for water, tight seal. Good luck on the next one, let us know if you need any help in the future. Mark, with Southside Plumbing