Relay switch made by the Power Equipment Co. Ltd

circa 1950

Mercury switch made by the Power Equipment Co. Ltd

circa 1950

Ferranti stall recovery switching unit

Mercury switch

circa 1950

Mazda 80W glass starter switch

1950-1960

Mercury tube No. 9 for switch

Mercury tube No. 9 for switch

Mercury tube switch

Ferranti switching unit

Switching unit