Fleetwood Natural Grain Carbon Arrows 500 Feathers 6 pk. Spine: 500;Inner Diameter: .244"";Point size: 5/16"";Grains Per Inch: 7.36 for 500;Length: 31 1/2"";Insert: 11gr;Nock: Fleetwood;Straightness tolerance: +/- .006"";Weight tolerance: +/- 2gr;Each arrow includes a replaceable insert and a nock;Packs of six arrowstable.productattributes, .productattributes td { border-bottom: 1px solid #ddd; border-collapse: collapse; padding: 2px; text-align: left; } Item Category Code: 1000 Product Group Code: 1000A Product Sub Group 1: 1000A1 Product Sub Group 2: 1000A1B Inactive: No