D'Addario's Nexxus 360 is a rechargeable headstock tuner that lasts for up to 24 hours of tuning on a single charge. Those small coin batteries are not cheap and they seem to never be ready to go when you just want to check your tuning. The Nexxus uses a Lithium Ion battery that is recharged using the included USB cable plugged into any (5V) socket in your laptop or phone charger.
The Nexxus 360 was designed with Ned Steinberger and features 360-degrees of rotation, so no matter where or how you have it attached to your instrument, you can still see the bright, full-color LED display.
The brand new D'Addario Nexxus 360 rechargeable tuner sells for $29.99 US MAP.