Since infrared thermometers are no touch, you can check the temp of yeast washing and yeast rehydration water and your starter wort without the risk of infection. I find mine particularly useful for rehydrating yeast.
Infrared thermometers should not be considered a direct replacement for your standard thermometer. A quality IR thermometer will give you a close approximation of surface temperatures. Note that steam seems to throw off readings. Uses include: Contained yeast rehydration water, chilled wort or starter temperature, kegerator, fermenter or fermenation area and beer tasting samples.
The Mix and Match sale allows you to get the volume discount (usually need to purchase 5 of the same item) by purchasing just two items. It’s worth noting that you can pick two different items to get the discount.
Note that both sales use ThermoWorks Holiday Gift Guide as their landing page. Sale Items and Mix and Match Items are clearly marked.