> For the complete documentation index, see [llms.txt](https://docs.rapt.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.rapt.io/equipment/rapt-pill-hydrometer-or-user-guide.md).

# RAPT Pill Hydrometer | User Guide

The RAPT Pill Hydrometer and Thermometer allows accurate, real time temperature and gravity logging during fermentation over either WiFi or (with a Bluetooth capable RAPT device) over Bluetooth.

When integrated with a RAPT device such as a RAPT Fermentation Chamber, the RAPT Pill can be used as a probe that controls your fermentation. 

This opens up a whole world of possibilities! You can use gravity or even gravity velocity as a trigger for temperature increases. No more guessing when its time to do a diacetyl rest - simply set your RAPT device to ramp up the temperature when the gravity change starts to slow down!

With a easy to clean form factor and a powerful 18650 Li-ion battery, these can last for months between charges.

We highly recommend the [wireless charging kit](https://kegland.com.au/products/wireless-charging-kit-for-rapt-pill-hydrometer) for the Pill, as this eliminates the need to open the housing for charging or to acces the Pill Captive Portal.

Need more then one Pill! Easy! Grab the colur of your choice - choose either the [<mark style="color:red;">Red Pill</mark>](https://kegland.com.au/products/red-rapt-pill-hydrometer-thermometer-wifi-bluetooth), [<mark style="color:blue;">Blue Pill</mark>](https://kegland.com.au/products/blue-rapt-pill-hydrometer-thermometer-wifi-bluetooth) <mark style="color:blue;">or</mark> [<mark style="color:green;">Green PIll</mark>](https://kegland.com.au/products/green-rapt-pill-hydrometer-thermometer-wifi-bluetooth)

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