uxcell 1/4 Inch x 5/16 Inch Alloy Steel Cup Point Socket Hex Set Grub Screws Black 100 Pcs Drive Type: Hex Socket; Head Style: Cup Point; Material: Alloy Steel Package Content: 100(+/-2%) x Grub Screw; Product Name: Grub Screw Weight: 100g; Main Color: Black Total Length: 5/16"; Thread Diameter: 1/4" Thread Counts: 20; Grade: 12.9