This is a Challenge Cutlery swell end jack knife. It was made between 1905 and 1928 at their Bridgeport, Connecticut factory. It is one of the better New England knives I have. It has two carbon steel blades. The spear point main is close to full. It has a long pull and a double cut wedge. It has a dynamite and equal snap at closed, half-stop and open. Someone matched the hardness on the blade and spring perfectly. There is a little left/right play when open. The secondary blade has seen some wear. It also snaps perfectly and has no play when open. It has dark wooden covers with evidence of some now-eroded initials or markings. They are unchipped and snug with the brass liners and steel bolsters. This is a really beautiful, rock-solid centenarian knife. The combination of wear to the covers and the condition of the blades boggles my mind. Imagine making something to be carried and used daily and having it last 100 years. Help it see another few in your collection.