Clamp-On Surface Temperature Probe 3/16" to 1.25" Jaw Opening For MD Series Digital Manifolds. All probes have 6ft lead. Probe Type, Surface. Common Uses, Surface temperatures of copper piping from 3/16" (5mm) to 1 1/8" (29mm), Response Time of 12 seconds and a range of -40˚F to 221˚F /-40C TO +105˚C.