Detonator used by DeAutremont brothers to blow up a mail car. Made of 5/8 inch thick wood joined with mortice and tenon and flathead screws. The device has a plunger, leather strap handle, two 1 1/8 inch high screws/wing nuts and metal advertising plate on top. The advertising plate cites "DuPont Blasting Machine No. 3, Will Fire 1 to 30 Fuzes" and provides instructions for use.