- Small PRO 2 sensors work with both the 21oz PRO 2 bottle and the 30oz PRO 2 tumbler
- Large PRO 2 sensors are specifically for the 32oz PRO 2 bottle.
- PRO 2 sensors are NOT compatible with older PRO models. To avoid potential damage to your PRO 2 Sensor, do not try to force fit with older models as the threads are different and they will not measure accurately. Each PRO 2 sensor is specifically designed and calibrated for ONLY the PRO 2 bottles and tumblers.