Entanglement devices (except in Robot Wars from series 10 onwards) Lasers above 1 milliwatt Visual obstruction Halon – a specific fire extinguishing gas effective as a weapon in stopping internal combustion engines. Note that current rules do not specifically ban Halon as it is no longer commercially available. Individual competitions have made exceptions to the above list. Notably, the Robotica competitions allowed flame weapons and the release of limited quantities of liquids on a case-by-case basis. The modern series of BattleBots also permits the use of flamethrowers and, as of 2016, untethered projectiles, provided that the latter are merely for show. Competitions may also restrict or ban certain otherwise legal weapons, such as banning spinners and other high-power weapons at events where the arena is not able to contain these weapons. A well-known example of this is the Sportsman ruleset. Arena hazards have also been granted exceptions to the list of prohibited weapons. Robot Wars in particular used flame devices both in the stationary hazards and on one of the roaming "House Robots". Unusual weaponry A very wide variety of unusual weapons and special design approaches have been tried with varying success and several types of weapons would have been tried had they not been prohibited.Entanglement weapons – Several early US Robot Wars competitors sought to immobilize their opponents with entangling weapons. Nets and streamers of adhesive tape were both tried with mixed success. Entangling weapons were prohibited in Robot Wars and BattleBots from 1997 onward, but the Robotica competitions allowed nets, magnets, and other entangling devices on a case-by-case basis, and Robot Wars allowed limited use of entanglement devices in Series 10.Flame weapons – Although prohibited for use by competitors in Robot Wars and the first edition (2000–05) of BattleBots, the rules for Robotica, the Robot Fighting League and the post-2015 version of BattleBots do allow flame weapons under some circumstances. RFL super heavyweight competitor Alcoholic Stepfather (unique for using mecanum wheels for movement around an arena) and Robotica competitor Solar Flare, as well as the later BattleBots series competitors Free Shipping and overhead pneumatic-pickaxe armed Chomp employing gaseous flamethrower weapons. Gruff is a BattleBots competitor that competed with its main weapon solely as a high power flamethrower (two as of season 5) with the help of a lifter, with moderate success. Flamethrowers are seldom effective weapons, mainly due to their effectiveness being limited for safety reasons, but are