【Solid Material】The garden auger bit head is made of premium manganese steel and the shaft is made of A3 steel, durable and not easy to deform. The surface with a glossy black painted finish protects the garden drill bits well from rusting. 【High Efficiency】Spiral design ensures efficient digging and soil dumping without difficulty. Use a drill at low speed (slow), then drill into the ground or suitable landscape, the auger drill bit easily digs a hole in seconds and works well even in slightly hard soil. Note: Not suitable for large rocks or solid stones 【Suitable Machine】Both garden drill bits work perfectly with any drill with a 3/8" or larger chuck. But you'd better use drills with a power of 18V or above (For cordless drill at least 14V) for a better digging experience and saving labor time 【2 Various Sizes】This set contains two auger drill bits 40 x 220mm and 80 x 300mm. They are used to quickly dig a hole of 40mm/80mm in diameter, and 220mm/300mm in depth. It helps you plant