Facom Bi-Hard Cobalt Hacksaw Blade-10 tooth per cm (668A.10) - the new 668 Series blades (668A/668B) are made from cobalt steel . Cobalt has a better resistance to warm-up, and contributes to the reduction of teeth wear. Multi-material use. Available in 10-packs only. (300mm, approx 12".......works in all standard size hacksaws). Note - 668A.10 and 668B.10 are the same item....no technical differences.