Monitor your extruder motor, ready to react if it starts to go over temp (options: panic, turn on a fan, vow to install an extruder fan). Similarly monitor your print bed (edges of my prints tend to warp if someone turns on the air conditioner and the room goes below 25 Celcius). The thermometer probes are housed in probe holders (snap on) and secured to your motor/ print bed with double-sided tape. No fuss or screws needed. The thermometer read-out panels are mounted onto holders (with a snug snap-on fit) that can swivel on a mounted base, to adjust viewing angles; avoiding glare/ reflections. This set up works on any printer, although the base for the thermometer holder is designed to mount on the Y-Axis arm of the Printrbot-Simple Metal. You could easily draw up a rod to make a stand or mount it anywhere your imagination takes you (dimensions: 5mm (W) x 7mm (H) rod with 2.8mm (dia) holes). The two holder panels provided are labelled - "EXT(ruder) Drive" and "Print Bed". If you need a holder labelled differently, drop me a comment and I'll be happy to customise it for you. I did think of throwing one more probe inside the Printrbot body but that has not given me any temperature-related problems so far... BOM: 2 x M3 8mm or 12mm screws (to secure panel holders onto base) Digital thermometer probes (I bought mine here for under USD2 each: http://www.aliexpress.com/item/Digital-LCD-Probe-Fridge-Freezer-Thermometer-Thermograph-for-Refrigerator-110C-Black-White/936092083.html) Double-sided tape (heavy duty, no real need for heat resistant type) Cable wrap (optional)