This is a new reproduction long-neck Lucas-style battery cutout switch. It is nicely made and in perfect, new condition. It is similar to the type of switch used on Austin-Healey 100-4, 100-6 and 3000 and some Aston Martins.
It would be a great addition for any older car for which you might want antitheft protection or isolation to reduce the likelihood of electrical fires during storage.