Vacuum-brazed diamond grit cuts faster and lasts longer Segmented teeth reduce debris and heat AutoStart pilot bit is spring-loaded, retractable shaft allows walk-free cutting without a pilot hole Pilot bit offers unique grind that starts holes accurately every time Plastic case Set includes: (1) mandrel, (1) AutoStart pilot bit, hole saws: (1) 1 4 inch, (1) 5 16 inch, (1) 3 8 inch, (1) 5 8 inch, (1) 1 inch, (1) 1-3 8 inch, (1) 2 inch, (1) 2-1 4 inch, (1) 2-1 2 inch