High Quality MaterialMade of sturdy steel, durable to use. With glossy black painted finish, the big cultivator bit is not easy to rust. Fast Digging Easily dig most soil types, even clay and rock. Makes planting jobs much easier and faster, save your back and let the spiral seeder do the work! Spiral Drill Bit Size 4.6cm diameter x 37cm length (1.8inch x 14.6inch) planter bulb with 0.8cm / 0.3inch non-slip hex drive. Easy to UseUse a 3/8'' or larger drill on low (slow) speed, drill into the applicable ground or landscape straight 37cm (14.6 inches) and lift it out of the hole; 18V or higher drill recommended; For drills without wire, a minimum 14V drill is recommended. Perfect forSuitable for professionals and home DIY projects, planting flower bulbs, bedding plants, grass plugs and nursery seedlings, fertilizing shrubs and trees for water aeration deep and even weed and root removal.