1、This is a brand new item. These diamond drill bits are made of high quality material to resist corrosion. A thicken diamond coating on the tops offers superior cutting strength for maximum drilling outcomes. 2、Easy to use, high quality. good performance, long life. These glass hole saw set along the drill bit facilitate the entrance of cooling water and escape of chips and other particles from drilling. Makes the drilling process easier. 3、Excellent for making clean and accurate hole on glass , tile and marble. 4、Works better with a electric drill (Excluding in this item). 8 different drill bits included with this glass drill bit set to meet various demands. Perfect for drilling glass, tile, porcelain tile, ceramic tile, brick, and stone. 5、The product is for making wine bottles with light strings, which can also drill through glass blocks. You can drill through bath tub tile, and put on a handle bars. Aquarium drill bit for overflow installation Features: -This is a brand new item. -Easy to use, high quality. good performance, long life. -Excellent for making clean and accurate hole on glass , tile and marble. -Works better with a electric drill (Excluding in this item). Specifications: Material: Metal Size: 10 / 14 / 18 / 20 / 26 / 32 / 45 / 50mm Package Includes: 1 x 8pcs Diamond tool drill bit hole saw set Note: When using the bit please add water to cool down the temperature to extend its service life.