Designed by Gerry Fox in the early 1970s, this carbine saw production sequentially as the Fox Carbine, the TAC-1, and the XF-7 Wasp, as it went through several different manufacturers. It is an open bolt, semiauto carbine sold in both 9mm Parabellum and .45 ACP – and you could get caliber conversion kits consisting of a bolt and barrel assembly to swap caliber on an existing gun. In 9mm they used Sten magazines, and in .45 then used M3 Grease Gun magazines.
The gun was marketed to law enforcement audiences as well as civilians, but never found any LEO success. A fully automatic version was also made, but similarly saw little popularity (because of the cost of NFA registration in the 1970s and 80s). Mechanically, the gun is somewhat akin to the Soviet PPSh, which an upper cover that hinges open and a bolt which is square on the bottom and rounded on top. The TAC-1 version had a few neat additional features, namely a combination lock built into the receiver and a battery in the fixed wooden stock to power a stun gun/baton device for police use. The Wasp replaced the wooden furniture with a fairly clever collapsing metal stock. In total, about 3,500 Fox carbines of all types were made, with production ending in 1983 when the ATF determined that open-bolt semiauto designer were too readily convertible into machine guns.
For much more information on these guns, I suggest having a look at FoxCarbine.net.