This is a very nice MC Gregory Los Angeles 4A 18 for Bb clarinet, serial number 3992. The mouthpiece is in good condition showing some standard cosmetic play wear. There is also a little bit of light wear around the beak. The facing profile is clean around the table, tip and side rails. Its original 4A 18 stamp at the bottom of the table is still very clear.
The tip opening on this piece measures .01.20mm/.047”.