This is the screw rim for the signature mouthpiece of John Putnam, Principal Horn of the Michigan Philharmonic.
This rim has 800-36 "Metric" threads that are compatible with Wedge M rims, PHC, and similar rims. The dimension at the joint is .689 inches (17.5 mm).
Specifications: Similar to PHC S18
ID - .721 inches, 18.3 mm at .04ÍÎÎ¢Í_ÎÎÎ£Í_ÎÎÇÎ into the cup
OD - 1.112 inches, 28.25 mm
Rim Width - .195 inches, 4.95 mm