This is a cable activated Starter Switch for MG TD MG TF MGA the Bugeye and the early MKI Midgets and MKII Sprites. Originally known as the Lucas type ST19 cable pull starter switch it does have to handle a lot of power traveling through it when the starter is engaged. This is our premium version of this switch and these are really good quality and made in England. We also sell a less expensive version that is part number 3H949.