That depends on what you are looking for.
If you are looking for more stable temperatures for longer single infusion mashes and would like the option to kettle sour, you will want the MTSs kit (Mash Tun Stabilization system). The MTSs include a 12V adhesive heating pad, a digital temp controller module, and a power supply. No tubing or pump required. It is not intended or capable of increasing temps for step mashing or heating strike water.
The heating pad is installed by taking off a removable panel from the bottom of the Mash Tun and sticking the pad on the underside of the 5-degree conical bottom. The heating pad is toggled on and off by the digital controller which is powered by the plug pack (includes either a 6 amp or 8 amp power supply).
If you are looking to recirculate your wort for better efficiency or want to mash at multiple temperatures to extract additional enzymes, you will want the RIMS from our eBrewing line-up. These can be directly hooked up to any of our eControllers (including the 1v eController, 2v eController, and 3v eController) and we even offer an essentials kit with tubing to help get you attached to a hotside brewing pump like the Chugger 7gal series.