Manfrotto Lock Knob
SKU:003603
Part #: R504,50S
Part condition: NEW
Substitute part: Replaces R516,22
This part also fits: 502HLV , 504HLV , 509HLV , MVAPANBARl , MVAPANBARM , 516 head
Note: Not for use with NITROTECH HeadsMeasures: 1.63 inches, 40.5mm
Retention Washer
Handle Collar
Pan Bar Handle
G3 Curved Pan Bar 
Long Pan Bar Knob
Medium MVAPANBARL