System includes: Cutter Head, (2) Carbide Cutters, (2) Cutter Screws, 7mm Pilot Shaft, (5) Trimming Sleeves, Allen Wrench, Star Wrench. The 4-sided replaceable 12mm carbide cutters (PKTRIMSX) will cleanly trim pen barrels up to 1" diameter. The included components will trim (9) tube diameters: 7mm, 8mm, 3/8", 10mm, 25/64", 10. 5mm, 27/64", 12. 5mm, 31/64". Smooth and square barrels are essential for pen kit parts to mount properly.