Carbide, center-cutting, four-flute mills precisely cut the groove necessary to install a Sako extractor on your Remington bolt for positive, reliable extraction. High-cobalt content improves feed rates for fast cutting. Order the cutter that matches the width of your Sako extractor. Mfg: Brownells SPECS: High-cobalt carbide. Order cutter that matches your Sako extractor slot width.