The SPK3 temperature pocket tool has convenient two-way temperatures with both a folding in-duct Rod temperature and an infrared 8:1 gun. The IR takes quick surface temperature readings, and the Rod measures in the duct easily with a hanging hook for hands-free testing. The SPK3 temperature tool also features max/min/hold functions, a backlight, and a display that flips depending on what temperature mode is chosen. The SPK3 is a great tool to quickly take in-duct, ambient, and register temperatures. It's a handy tool to assess a system and it fits conveniently in your pocket. The ROD has a sharp, narrow tip to easily insert into duct work, and the hanging hooks allows you to take hands-free measurements. The bright back lite display flips between the IR and ROD measurements so readings are always easy to view. Plus this handy tool quickly calculates T1 - T2 across both the IR and ROD modes, or a combination of the two.