The most widely used cord grip on tour the tour velvet bct cord comes standard with brushed cotton technology bct a tighter weave cotton twill fiber that delivers a comfortable cord grip the tour velvet bct cord features all of the great traction and all weather performance that made the tour velvet the winningest cord grip on tour material core size weight 35 g outside diameter brushed cotton technology 60 round 505 standard brushed cotton technology 58 round 525 standard brushed