I purchased this Matrix clip on tuner to help me to keep my fiddle in tune and because, unlike some other tuners, it can be used for cross tuning as well.
The Matrix MA-8001 chormatic tuner can be set to tune violin, guitar, bass, and ukulele. It features variable pitch reference from 430Hz-450Hz, vibration sensing accuracy, a bright full color LCD display with note and needle-style indication (Yellow/Left=Flat, Red/Right=Sharp, Blue/Center=In Tune), and a secure clip-on design with fully adjustable, 360-degree swivel and tilting mount for optimum viewing at any angle. It is powered by a 3V CR2032 (flat) battery which is included.
This tuner senses the vibrations of the instrument when attached to it. Unfortunately, the clip is rather small, so it can only be attached to a tuning peg or the chin rest. Attached to a tuning peg, it can be adjusted so you can see it as you tune. You will need to move it from a peg on one side of the pegbox to a peg on the other side, depending on what string you are tuning, or it will get in your way. Attached to the chin rest, you can’t hold the violin up to your chin, but you don’t have to move the tuner at all while tuning. Take your pick.
I thought the directions for operating the tuner were a bit lacking, but that may just be because of my inexperience with using such a device. However, once I figured it out, it worked extremely well. As I bowed a string, the LED screen showed what note I was playing. If flat, the left side showed a number of yellow columns depending on how flat. If sharp, the right side showed a number of red columns depending on how sharp. When perfect, the one blue column in the center appeared. No guesswork involved.
I am pleased with the Matrix MA-8001 Chromatic Clip-On Tuner. I purchased it from the Fiddlershop for $14.99.