Carbon express arrow maxima red 350 w/2" vanes 6pk FEATURES -6 pack-Size: 350-9.07 grains/inch*-0.342" spine-0.300" diameter-Fletched with BlazerA(R) Vanes-LAUNCHPAD(TM) Precision Nocks-Each arrow comes with a Carbon ExpressA(R) proprietary BullDog(TM) Nock Collar-Dynamic Spine Control - Patented hi-tech carbon material construction controls arrow flex to theRED ZONE(TM)*Bare shaft weight Other Features: Dynamic spine control uses different carbon materials to control arrow flex to the red zone making broadheads fly better.342" spine,.244" id,#1 insert