Universal Rig. The other can be mounted on the bottom of the plate as you require it to enable quick switching among handheld, stabilizer, and tripod shooting. If you don't need a QR plate for Arca, then you can use the 1/4"-20 and 3/8"-16 threaded hole on the bottom of the plate to mount the quick release plate you need, such as for Manfrotto etc.
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