What DOES the switch on the bottom of a Carrera slot car

Is Carrera the only maker of 124 slot cars? Also, do 124 scale cars only come as digital or can you get analog too I am very new at this and

Scalextric Cars Digital · Track · View All · Carrera · Buildings Borders & Figures · Carrera Cars 1:24 · Carrera Evolution Cars 1:32 · Carrera GO Cars 1:43

carrera slot car set slot cars, steam engines, paints, tools and hobby supplies CARRERA · HPI Racing · Revell · Scalextric · Biante · Classic Carlectables · Dragon · Estes

carrera digital slot cars All Carrera Digital 124 cars have a switch on the chassis that allows them to run on analog systems in addition to Carrera Digital