Manufacturer: RCBS 12065
Case trim die doubles as a visual case length gauge. Run a case into the trim die. If the case sticks out above the top of the die, it's too long. File the case down until it's flush with the top of the die. Then, debur the case mouth with a deburring tool. Die is case hardened and hand polished. Heat treated to withstand a file bearing against the top surface without damaging the die.