About This Item.Quality Material - This drill is made of hard alloy, which is tough, tough and durable. Self-tapping drills can be screwed quickly and accurately without the need for tedious pre-drilling. No risk of cracks and crevices.Versatile- This bit will suit most drills and can be best tightened with electric hand drills to avoid climbing and slipping, especially for metals due to its harder.Largemutil - The drill kit is ideal for drilling on all materials, including tile, concrete, ceramic tile, bricks, wood, plastic, glass, masonry, etc. Remark: When drilling hard materials (glass, tile, marble or granite), lubricate with water.Big discounts - Each pack includes two different styles, one is a black triangle diamond and the other is an orange diamond. There are 10 pieces in total. The sizes are 6mm, 6mm, 8mm, 10mm, 12mm, which can meet your different needs.Service - If you have any questions, please feel free to contact us; we will get back to you within 24 hours. We will process your return or refund.See more details.