Descriptions:

Drill stop bit can be quickly and easily adjusted at any point on drill bit flutes, helps to drill holes to exact depths, prevents under and over drilling.
Set-screw type drill stop is suitable for low axial loads and simple positioning. It is great for jobs that use a bit and need precision.
Strong and durable steel with black-oxide finished for better corrosion resistance. Set screw type will stay sturdy when tightened and is specially designed not to break the bits.
Theses fit around drill bits for consistent drilling depth. Great for dowels and hole fixing.

NOTICE: For maximum holding power, make sure the set screw material is harder than your shaft material. Do not move the drill bit stop after tightening.

Specifications:
Product Name: Drill Bit Stop
Material: Carbon Steel
Thickness: 8mm/0.3 inch
Internal Diameter: 4mm/0.16 inch, 5mm/0.2 inch

Package Contents:
4 x Drill Bit Stops
2 x Hex Wrench