Originally posted by inthere10x: The 125grn and 150grn the weight difference is in the ferrule. Check thier website the measurements on the blades 2 3/16" x 1 1/8" for the two and four blade 125grn and 150grn. I'm no expert so I'll have to weigh them at work to be sure, but almost sure it's in the ferrule. The 85grn and 100grn each use different blades.