Kirk USA solid single piece L bracket for arca swiss tripod head. Used with A7Riv to allow both portrait and landscape orientation in a single adapter on an arca swiss compatible head. Many brands make this in two parts which may introduce flex if it loosens. This is a solid piece option from a premium US brand. Bought new last year from B&H for 200 + shipping from US. Has a clipped in Allen key. Please note that it does not have a tripod thread on the bottom as they instead put in a Quick connect port. From B&H description: Kirk BL-A7R4 Highlights One-Piece Design L-Bracket Arca-Type Compatible Dovetail Mount Anti-Twist Flanges Slotted Design for Side Port Access Access to the Battery Door No Interference with Tilting Screen Sensor Centering Lines on Each Axis Black Anodized 6061-T6 Aluminum Built-In Hex Wrench Storage System Machined Hand Strap Loop

Able to change vertical or horizontal orientation without losing the center of axis. Dovetail design is Arca-type compatible and scored with sensor centering lines on the back of the bracket. Complete access to the battery door and camera ports, and with no interference to the tilting of the screen. L-bracket is machined from 6061-T6 aluminum with an anodized black finish.