SU-16 refers to a series of semi-automatic rifle

Semi-automatic rifle

A semi-automatic rifle is a type of rifle that fires a single bullet each time the trigger is pulled, automatically ejects the spent cartridge, chambers a fresh cartridge from its magazine, and is immediately ready to fire another shot...

s and carbines manufactured by Kel-Tec CNC Industries, Inc.

Kel-Tec

Kel-Tec CNC Industries Inc. is a United States manufacturer of firearms. Founded in 1991 and based in Cocoa, Florida, the company has manufactured firearms since 1995, starting with small, affordable semi-automatic pistols and expanding to rifles. Kel-Tec is a privately-owned Florida corporation....

 of Cocoa, Florida

Cocoa, Florida

Cocoa is a city in Brevard County, Florida, United States. The population was 16,412 at the 2000 census. As of 2008, the estimated population according to the U.S. Census Bureau was 16,478. It is part of the Palm Bay–Melbourne–Titusville Metropolitan Statistical Area.-History:Cocoa was...

, referred to in Kel-Tec's marketing as "Sport Utility rifles". The SU-16 series is notable for its compact, lightweight and simple design; and for being able to be broken down and folded into a compact configuration for transportation and storage. While the barrel, bolt-carrier and mechanism are steel, the SU-16's stock, receiver, and forend are manufactured of high-strength polymer plastic.
All variants of the SU-16 are chambered in 5.56×45mm, and are capable of using standard M16 STANAG

STANAG

STANAG is the NATO abbreviation for Standardization Agreement, which sets up processes, procedures, terms, and conditions for common military or technical procedures or equipment between the member countries of the alliance. Each NATO state ratifies a STANAG and implements it within their own...

 compatible magazines (where not prohibited by state or local law).