Parker RED HOT Carbon Crossbow Bolts are engineered for today s crossbows shooting over 300 fps. The front 2/3 of the arrow is heavier Buff Tuff material for added strength and penetration. The Back 1/3 of the arrow is made of lighter and stiffer Buff Tuff Plus which aids in recovery out of the bow. Features:. Built-in Weight Forward design. Exclusive Hevi-Hit oversized insert (51 grains) increases penetration and shaft strength. Laser checked for consistent straightness and spine tolerances. Mag-Nock Moon nock (13.7 grains) for added level of performance.. Fusion Vanes by Duravanes (NEW for 2009). 425 Grains (using a 100 Gr. point). Recommended for 100 gr. broadheads