These “bump” helmets are worn by aircraft carrier deck crews. They are made from several disconnected plastic shells secured to a cloth cap, allowing them to be lower profile and more flexible than an actual helmet. The shells’ color corresponds to the wearer’s job on the flightdeck (source: https://www.history.navy.mil/content/dam/nhhc/news-and-events/multimedia%20gallery/Infographics/FINAL_RainbowJerseys_highres_PDF.pdf). White helmets mean safety (quality control) and medical personnel.
Besides aircraft carrier flightdeck crews, these helmets were sometimes repurposed for VBSS (Visit, Board, Search, and Seizure) personnel during the 1990’s for raids due to the low profile combined with integrated communications. Thanks to some “glamour” shots, these helmets are commonly associated with VBSS in video games (source: https://combatarms.fandom.com/wiki/VBSS_Helmet) and action figures.