The BM869S can handle 2 K-type probes and display (and log on PC) the temperature difference. This is more useful than it sounds because the 2nd probe effectively cancels changes in ambient temperature. The point is however, for good accuracy you need 2 identical K-probes and the plug adapters need to be of good quality and identical too, in their thermal properties. The BKB32 plugs are great for this purpose and work perfectly
