We produce export quality roofing bolts for coal mines in different thickness, lengths and shapes. Roofing bolt (crochets) set of five containing umbrella steel washer , flat round pvc washer, small round steel washer nut and rod dully zinc plated available thread size: 6mm, 7mm & 8mm, available lengths: 250mm & 300mm, We have range of Roofing bolts, J hook.