The Franchi SPAS-12 (Sporting Purpose Automatic Shotgun) is a dual-action police shotgun produced in Italy between 1979 and 2000, and imported into the US until 1994. It can be operated either as a semiautomatic or a manual pump action, as a way to allow rapid semiautomatic fire with buckshot or similar ammunition but also function manually with lower pressure less-lethal types of ammunition (rubber slugs, beanbags, tear gas, etc). The gun was purchased by a decent number of law enforcement agencies, but it is far better known for its use in movies and video games, where its distinctive military styling makes it very popular with designers and prop masters.
Still, there are a couple interesting elements worth looking at on the SPAS-12. For one thing, they were subject to a safety recall for a safety selector which could sometimes cause the gun to fire when being switched from safe to fire. And, of course, there is that hook thing on the stock. What's that for, anyway? I'll show you...