Accessibility probes Model ZLT-U01 Model ZLT-U01: UL Finger Probe This is the â ULâ test finger, researched and designed by UL, and required by most UL Sandards. Palm simulator and restricted joint movement simulates human finger movement. The handle is made of nylon. The finger is made of stainless steel. Conforms to : UL507, UL982, UL1278, UL1062, UL1310, UL474, UL60065