Excalibur"s Boltcutter B.A.T. (Blade Alignment Technology) Broadheads are tunable, allowing you to align the blades so each broadhead flies identically. The key is that the blades on each individual broadhead are aligned the same way when loaded in your crossbow. Boltcutter B.A.T. Broadheads allow you to do just this with a simple wrench and hex key. Once aligned, your groups will be dramatically tighter. Boltcutter B.A.T. Broadheads are made of high strength stainless steel and, the proven 150 grain heads (with 1-1/16" cutting diameter) increase front of center weight for pinpoint accuracy when shot out of today"s high performance crossbows. Model 6673.