The HANS device is a neck-protection safety device worn by many Monster Jam drivers. Its name means Head and Neck Support, and it is designed to reduce dangerous head and neck movement during a crash.
The device sits on the driver’s shoulders and works with the shoulder belts of the racing harness. Tethers connect it to the helmet, helping limit forward movement of the head while spreading forces through the shoulders and torso instead of allowing the neck to absorb the full load.
HANS devices became widely known through professional auto racing, particularly after head-and-neck restraints gained greater attention following serious racing accidents. Major racing organizations later required approved head-and-neck restraints in many categories. Monster trucks face their own hazards: high jumps, hard landings, rollovers, and abrupt changes in direction.
“HANS device” is often used as a general term, although Monster Jam’s official safety material notes that drivers may use different approved head-and-neck restraint brands or styles. The broader category is a head-and-neck restraint; HANS is the canonical name associated with the device in the question.