Screw Loose Black Alloy Button Head “Big Head,” a 650 piece bulk m3 hardware kit. Perfect for multiple custom builds and maintenance for a variety of R/C trucks and cars. This Black Alloy BHCS Kit includes 150 SS nylon locknuts, 100 flat washers and 400 m3 screws. The screws include 50 pieces each of the following m3 button head lengths: 6mm, 8mm, 10mm, 12mm, 14mm, 16mm, 20mm, and 25mm. All black hardware is 12.9 class black oxide alloy. The nyloc locknuts and flat washers are A-2 (18.8) stainless steel.