Big 3.7-Inch anti-aircraft guns, built at Peterboro, are dependent on fuses from the General Engineering Co. plant at Scarboro. Here a 3.7 ack-ack gun is shown on display at the Geco plant, being inspected by five workers, Frances Russell, Audrey McNabb, Sydney Cumberland, Norma Clark and Betty Carroll. One of these guns can throw hundreds of heavy shells every hour.