Nut sensors -- Norgren Automation Solutions

 NAS nut sensors are available in toughened and standard-duty versions for M5, M6, M8, M10, and M12 nuts. The sensors feature nut and thread sensing; hidden nut detection; thread sensing in tapped holes; thread quality checking; and easy ergonomics.
Norgren Automation Solutions, 44831 N. Groesbeck Highway, Clinton Township, MI 48036, (877) 688-7367), www.norgrenauto.com