Mac-14 clamp accepts both Bogen 3517N / Manfrotto 200PL-14 RC2 Plates AND Arca / RRS Compatible QR Plates. 66lb Max load! Eliptical Ball for progressive resistance. Y-axis diameter 0.03mm longer than the X-axis. Single notch design. Super strong shell. All Metal knobs. For long term durability. Panning Base Scale. Independent Pan Lock Knob, 360° panning movement with calibrated precision, precisely capture overlapping panoramic images. Panning Base is laser-engraved with index marks from 0°-360°, with increments at 5°. Ball Diameter: 44mm. Base: 55mm. Height: 96mm. Weight: 493g. Max load: 30kg (66 lbs). Bottom thread: 3/8" with 1/4" adapter.