CENTERLOCK FEATURES SHALLOW SCREW CHANNEL FOR ADJUSTABLE FIXED POSITIONING. DEEP SCREW CHANNEL FOR FREE-SLIDING BETWEEN STOPS OR FOR BREAK-AWAY RIGGING. PATENTED O-RING INSERT DESIGN. TAPERED CLAMPING SURFACES FOR MAXIMUM HOLD ON EVEN VERY FINE LEADERS. TEXTURED OUTER SURFACES FOR GRIP AND EASY IDENTIFICATION OF HALF TO ROTATE. RAZOR CUT LINE RETENTION SLITS PREVENT LINE FROM [a |]