Parts List: 2 x Forstner Bit Extension 2 x Wrench Highlight description: Forstner Bit Extension: Extend the shank bit by an additional 169mm, 254mm to help you drill flat holes with a standard drill bit or to start deep hole turning projects such as on larger vases or containers Size Information: The inside diameter of the collets is 9.7 mm, 10.5 mm.This tolerance is very small and designed to accept drills with shank sizes of 2/5 inch, 3/8 inch or slightly smaller Sturdy Material: Made of 45# steel, very sturdy and can be used again and again Easy to Use: Includes two set screws and hex wrench. To secure the shank in place, use the hex wrench to tighten these screws Anti Slip: Traditional drill extensions tend to slip when using hardwoods, so we developed a non slip design for the parts attached to the drill rig that allows the jaws to grip the extension securely Detailed description: Description: This forstner bit extension is used to extend shank drill bit an extra 169mm,254mm. It adopts steel structure, which can ensure it is strong and enduring. Feature: Easy to Install: The package includes 2pcs forstner bit extension and 2pcs wrenches. To hold the shank in place, use a hex wrench to tighten these screws. Enduring: This forstner bit extension is made of steel material, which can ensure enduring. It can help you use a standard drill bit to drill flat-bottomed holes or start deep hole turning projects. Specification: Product Name: Forstner Bit Extension Material: 45# steel Dimensions: Length 169mm, shank diameter 137mm, model 10.5mm Length 254mm, max. cutting depth 62mm, shank diameter 222mm, model 9.7mm. Color: Silver Note: 1. There may be slight differences between the picture and the actual color of the commodity. We will try our best to show you the exact color. 2. Please allow slight dimension difference due to manual measurement. Sturdy Material: Made of 45# steel, very sturdy and can be used again and again Forstner Bit Extension: Extend the shank bit by an additional 169mm, 254mm to help you drill flat holes with a standard drill bit or to start deep hole turning projects such as on larger vases or containers Size Information: The inside diameter of the collets is 9.7 mm, 10.5 mm.This tolerance is very small and designed to accept drills with shank sizes of 2/5 inch, 3/8 inch or slightly smaller Easy to Use: Includes two set screws and hex wrench. To secure the shank in place, use the hex wrench to tighten these screws Anti Slip: Traditional drill extensions tend to slip when using hardwoods, so we developed a non slip design for the parts attached to the drill rig that allows the jaws to grip the extension securely