Aluminum body 0.40 lbs; 3.140 in. Lg; 1.770 in. W; 1.010 in. Max thk; normally closed (n/c) interrupter, input at port no. 3 must displace the piston valve to allow transfers detonation between installed smdc/cdc ports 1 & 2 to close or open a path for detonation transfer between 2 end-to-end smdc/cdc lines