SILENCIO™ POWER GRIP BARREL BACK (S63 AND PWR COMPATIBLE)Silencio Power Grip Barrel Back (S63 AND PWR INSERT COMPATIBLE) This Silencio GRIP barrel back works with the ALL NEW Planet Eclipse PWR inserts and the S63 Barrel System. As the name suggests this barrel back has machined knurling for extra grip when your hands are wet, muddy or slick. The grip back also eliminates the "cut out" window so that the colored PWR inserts don't clash with your custom colored marker. Features Compatible with Planet Eclipse