The ARWEN 37 (ARWEN stands for Anti Riot Weapon Enfield) is a British non-lethal launcher.
The ARWEN 37 was designed in 1977 by RSAF Enfield after a request to make a multi-shot weapon to replace the single-shot Federal Riot Gun. Three prototypes were made for testing; a semi-automatic prototype, a rotary drum magazine prototype, and a pump-action prototype. The rotary drum magazine prototype won and is in production today.
The weapon uses a special type of 37mm round with a rebated rim on its case. The round has a total of nine variants:
- RO1 - Standard impact baton
- RO2 - CS smoke
- RO3 - Irritant impact baton
- RO4 - White/colored screening smoke
- RO5 - Barricade penetrating irritant
- RO6 - Muzzle blast irritant
- RO7 - Multi-ball area impact round
- RO8 - Soft-tip impact baton
- RO9 - Training round