Intake air temperature / pressure sensor.
Commonly used for (but not limited to) 400cc, 500cc, 700cc and 800cc engines, such as the Hisun HS400, Hisun HS500, Hisun HS700 and Hisun 800 4x4 ATVs and Hisun Tomoto 800 / Strike 1000 UTVs, as well as many other clones, rebrands and similar displacement machines.