HIGH-QUALITY MATERIALS: The 3/16 inch masonry drill bits are made of high quality carbide YG8 alloy with cross four-head and anti-rust treatment,which are more accurate,smooth,anti-rust and wear resistant,and extend the usage life. NON-SLIP HEX HANDLE&U-TYPE GROOVE SLOT: hex handle design,makes the drill bits are tighter than the round handle & triangle handle,U-type groove slot design brings fast drilling dust removal, ensures drill bits to be held tightly and stably in power drill. APPLY FOR MULTIPLE PROJECTS : Easy to drill porcelain tile, hardened steel ,ceramic tiles, glass, marble, granite, brick, concrete, wood, iron, copper, aluminum, wood, steel plate, plastic, etc. If you drilling high hardness material please cool with water or cutting oil and control speed. EASY TO INSTALL:The 3/16 " carbide drill bits can be installed in most general drill, electric drill, hand drill and bench drill,ideal for drilling fastner holes for glass cutting, bathroom and shower installs, drilling and fastening mirrors, setting concrete screws in tile and etc. PACKAGING INCLUDES: The concrete drill bit set comes with 3/16" (5mm)*10 pcs, and includes a portable handheld case for you carring around. 1