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.
Also at ThermoWorks:
ThermoWorks is marking down Thermapen One by 25% as part of a limited early fall sale. No coupon code required. Applies to red, yellow and orange only.
Price, promotions and availability can change quickly. Check the product page for current price, description and availability prod:thermoworks1224