Can this plate be attached to the left side of a hawklock cage for canon R5II to enable vertical shooting with arca Swiss head. Will it block access to usb port ? Is this the best attachment for this or should I look at a different attachment? Thank you

This plate 2146B can be attached to the left side of the cage for vertical shooting, but requires one more 1/4" screw, which is included in the screw set AAK2326. It won't block the USB port. However, it is recommended another ARCA type plate for you, the plate of product 4234. You are welcome to contact us at smallrig@smallrig.com to buy one. It is not list separately for sale. Thank you. https://www.smallrig.com/SmallRig-Arca-Swiss-Manfrotto-Compatible-Mount-Plate-Kit-4234.html https://www.smallrig.com/smallrig-screw-set-for-camera-accessories-aak2326.html

I ordered and received 3 2146B Quick Release Plates (Arca-Type) from Amazon. One of the three is missing mounting screws. How do I get a replacement that is usable?

The screws can be purchased. The product ID is AAK2326. Please check it out here https://www.smallrig.com/global/smallrig-screw-set-for-camera-accessories-aak2326.html

Will this work with a sony a7c without a cage?

It is require a cage to work with this plate.

Quick Release Plate ( Arca-type Compatible)

Name: Quick Release Plate ( Arca-type Compatible)
Brand: SmallRig
SKU: 2146B
Price: 19.99 USD
Availability: InStock
Rating: 5 (12 reviews)