Fairyweight

The Fairyweight class is for robots weighing up to 150 g (0.33 lb). It's the smallest common weight class, and one of the cheapest and easiest ways to start building. In the UK, Australia and New Zealand, the same class is called Antweight – so a "150g antweight" overseas is a fairyweight in the US. See Robot Classes for how class names vary.

Rules

• SPARC: 150 g, called Fairyweight in the SPARC Tournament Procedures. Shufflers can weigh 187.5 g, non-traditional drives 225 g, and walkers 300 g (see Multibots, Walkers and Shufflers).
• UK: the FRA and Antweight World Series call this the antweight class. AWS rules also require the robot to fit inside a 4-inch (101.6 mm) cube, and give non-rolling robots 225 g, though not every UK event enforces the cube.[1]
• Some events run a non-destructive 150 g class, with no active weapons or limited ones.
• NHRL doesn't run 150 g.

Typical builds

• Drive: N10 or N20 micro gearmotors (see Insect Class Motors).
• Electronics: an all-in-one receiver and ESC board such as the Malenki-Nano is very common (see Radio List). Small servos power flippers, lifters and grabbers.
• Battery: typically a 2S LiPo of about 120–300 mAh (some kits use 3S).[2]
• Materials: mostly 3D printed, especially TPU (see 3D Printing), with titanium, steel or carbon fiber parts on top-level robots.
• Common designs: wedges and pushers, servo flippers and lifters, grabbers, and small spinners.
• Arena: SPARC recommends at least 3/16" polycarbonate walls and a 3 × 3 ft floor for full combat (see SPARC Arena Construction Best Practices).

Getting started

Fairyweights are a great first robot: parts are cheap, robots are quick to build and repair, and you can test them at home in a small test box.

• Kits (as of October 2026) include complete kits from Turnabot (around $175–180 before radio and charger), drive kits from Bristol Bot Builders (UK), and the Combat Robotics NZ kit. See Kits.
• Printable designs: there are well over a hundred free 150 g designs listed on the 3D Printing page.

Where they fight

150 g is one of the most common classes at US local events, and the main small class in the UK, Australia and New Zealand. Find events on RobotCombatEvents.com (see Events).

See also

• Antweight – the next class up (1 lb)
• Robot Classes
• Kits and 3D Printing