About this item 【IDEAL COMBO SET】7 countersink drill bits size of Ø7/64”(3mm), 5/32”(4mm), 13/64”(5mm), 1/4”(6mm), 9/32”(7mm), 5/16”(8mm) combine with Ø19/32”(15mm) countersink pedestal, 13/32”(10mm) combine with Ø45/64” countersink pedestal. 3 countersink bits with most commonly-used sizes of Ø12mm(1/2"), 16mm(5/8"), 19mm(3/4") A 1/10”(2.5mm) Free Hex Key Wrench Plus. Come with a portable plastic case for easy convenient select, storage and organization. 【PREMIUM QUALITY】Made with industrial grade high-carbon steel, great hardness provides sharp edges, high strength takes bits with superior cutting capactiy and durability. Ideal for household woodworking and DIY Projects. 【EFFICIENT DESIGN】For 7 countersink drill bits, 3-point tricuspid ensures drill process accurate and fast, no offset, slip and bias during drilling; 2-spiral flute makes chip removing easy and efficient. For 3 countersink bits, 90°on the point & 1/4" hex shank for quick change make the countersink process convenient. All drill bits get 5-edged chatter-free chamfer cutter pedestal design makes countersink precise and smooth. All cutting edge are well hardened and honed for sharpness. 【REMOVABLE& ADJUSTABLE】Perfect for Wooden planks, Fiberboard, Particle board, Plywood, Plastic, PVC and soft metals. Suitable for hand drill, bench drill and electric drill, #12，#16, #19 are especially fine for quick drill.The drilling depth of countersink drill bits are adjustable by screws with various lengths; Meanwhile, their bits are removable for easy cleaning, sharpening,and replacement. × NOT for hard metals or steel board. 【SOPHISTICATED DESIGN】Extra straightening drill bit with exquisite countersink pedestal provide user a method of drilling a countersink hole with 1 time drill process.Extra straightening drill bit makes the drill hole accurate and smooth, exquisite countersink pedestal creates proper countersink structure with efficient experience.