This remote pressure switch is especially designed for WF-501B Flashlight. With this switch, you are able to line control your Torch. Function: Remote Pressure Switch Compatibility Models: WF-501B LED Flashlight Suit for flashlight which has the same metal case design Size: 3cm x 2cm x 2cm - 1.18inch x 0.78inch x 0.78inch Diameter of Remote Pressure Switch: 23.5mm Material: Aluminum,plastic Color: Black Notice: Before you bid this item, please make sure this switch fits your torch, because some versions of the torch in the market might be different Package Contents: 4 x Remote pressure switch for 501B Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.