Permits selection between two batteries for starting, charging, or operating both batteries in parallel; For 6, 12, 24 or 36 volt systems; 230 Amps continuous, 345 amps momentary (5 minutes); Surface or rear mount; Conforms to US Coast Guard standards for ignition protection; Positive click-stop on all positions; Durable marine-grade polycarbonate case; 60% Larger ‘sweep’ contact area for improved performance and longer switch life; Dimensions: 5-1/2″ dia. x 2-5/8″; cable lug size: 3/8″ ; Fits most competitors mounting hole patterns