The CRL Digital Tin Side detector determines the tin side of float glass without the use of an ultraviolet bulb. There are several advantages to using digital technology to determine the tin side, such as being able to use this meter on either side of the glass. Just position up to the glass surface and depress the button, the large display clearly states if the meter is on the tin side, or if the tin is on the opposite side. With this new technology, the user no longer has to interpret the reflection of the UV light to make a subjective guess as to which surface is the tin side. There is no need to replace UV bulbs with this new Digital Meter, and the digital technology makes this meter very rugged, portable, and more energy efficient than other models. Operates on one 9V DC Battery.