M4 X 4mm Grub Screw MS Black oxide (Dia. 4mm, Length 4mm)

Diameter: 4mm 
Bolt Length: 4mm 
Material: Mild Steel (Black oxide) 

The M4 x 4mm Grub screw is 4mm in diameter and 4mm long. Made from Mild Steel material the grub screw has a black oxide finish that will protect it from any sort of corrosion.

A grub screw is generally used to secure an item against another item. It is commonly used as a locking device, particularly on custom modified Gears, pillow ball bearings, taper locking bushes, pulleys or adjusting rings. 

Grub Screws are designed with a hexagonal internal drive in the head, allowing them to be tightened and loosened with an Allen key.