At 3x the volume and weight of our original Tilt hydrometer, the Tilt Pro's larger size allows us to more than double the battery life with preinstalled Energizer AA lithium batteries that will keep it powered for 3 to 5 years depending on use. So much time you may forget your Tilt actually runs on a battery! The extra size and weight comes with an extra bonus: improved specific gravity stability at high krausen so you will see a steadier read-out on your iPhone, Android, or Raspberry Pi. In addition, we have boosted range with a high-gain antenna that in testing increased range by 20% vs. our original Tilt. Now you can see your Tilt through thicker heads of foam and heavier stainless steel walls. To top it off we've included the extra decimal of precision available from the sensors and to the read-out so there are now decimal degrees Fahrenheit as well as higher resolution Celsius. Specific gravity now reads out to the 10,000th place (for example 1.0000). You can now see fermentation activity dropping less than a brewer's point per day. In all we've made several adjustments we believe the craft beer professional (and serious home brewer) is sure to appreciate.