Bitzenburger Precision Die Cast Clamp shoe_size_8 21 AH battery will get size_Small 21 AH battery will get you up to 60 miles on 1 charge Proven Sitka Gear durability and performance season after season right and left helical clamps are ground with a radius to achieve a true helical fletch• Hollow recess allows for thumb and fingertip control preventing slippage in the hand• Graduated scale at the rear base of the clamp allows for consistent spacing of feathers and vanes accurately from the nock• Knife edge on base of the clamp eliminates build up of surplus glueNote: The steel plate is cased into the straight clamp Die Cast Clamp