24″ is long enough for most mash tuns to check temperature without any concern of getting the thermometer body wet. I have both of these. See: Hands on Review: ThermoWorks 12″ and 24″ Digital Thermometers – RT610B-12 and RT610B-24
As of this posting, the 24″ version is marked down to just $21. That’s a whopping half of discount.
Price, promotions and availability can change quickly. Check the product page for current price, description and availability prod:thermoworks1224