Testo 0628 7516 temperature probe for surface measurements ntc testo 0628 7516 this testo temperature probe with ntc sensor is ideal for carrying out surface temperature measurements a hole in the probe block allows you to securely attach it in the required location for optimum heat transfer between the surface probe and the measurement object we recommend using a silicone thermal conduction paste the probe can be used with any testo product with an ntc sensor input testo 0628 7516 temp