The QLB-50 Quick Release Clamp by FLM is an open channel Arca-style lever clamp that allows for different size quick release plates. It has a safety pin so that plates will not slide out of the clamp when it is loose. Built-in bubble levels helps align your camera vertically and horizontally.
The easiest and quickest solution for locking camera plates securely in place with a new lever-actuated system. One jaw is adjustable to accommodate various Arca plate sizes, then the lever can be opened and closed quickly. A locking pin ensures that the QR plate cannot slip out of the base when opened. This base is additionally equipped with a bubble level to facilitate horizontal alignment of the camera. Arca-compatible and adjustable to various Arca plates.
Here is a short instructional video: https://www.youtube.com/watch?v=3dzmSqmH8Ew&t=22s