Jobu Design QRR-138 Ballhead Threaded Hole Quick Release Replacement Clamp Jobu Design QRR-138 Clamp - 6mm Metric Bolt (2) - Jobu Design 5 Year Warranty Compatible with: Manfrotto 484 RC2Manfrotto 352 RCManfrotto 488 RC2 (requires small modification to clamp)Arca Swiss B1 (requires longer bolt)Manfrotto 468 MGRCO (requires modification to clamp) Warranty: Jobu Design 1 year warranty