Shakes not quickly, but surely. Worthy of being bought. Although I thought about buying a 2022 analogue, but the action did its job . Its pros: It switches itself off when the required (user-set) pressure is reached. Different cons: It is not convenient to store in the trunk, it would be more convenient, or make Velcro on the body, or a flatter body. Now it travels all over the trunk . I will glue the Velcro and can be attached to the back of the seat.