Premium MaterialMade of solid steel for durability. With a glossy black paint finish, the cultivator bit won't rust easily. Fast DiggingEasy to dig most soil types, even clay and rocks. Make planting easier and faster, save your back and let the auger do the work! Auger Bit Size8cm Dia x 30cm Long (3.1"x 11.8") Planter Bulb with Non-Slip Hex Driver for 10mm (3/8) Bits ") or more. Compatible Using an 18V or higher drill at low (slow) speed, drill directly into the applicable ground or landscape for 30cm, then pry the hole; for cordless drills, it is recommended to use a drill of at least 14 V. GREAT FITSuitable for professional and home DIY projects, grow flower bulbs, flower bed plants, grass cuttings and seedlings, fertilize shrubs and trees for aeration in deep water, and even weed and root removal.