Measure the thickness of individual coating layers (must be alternating or different colored layers) after the fact using the Tooke Gauge. This powerful gauge is hand-held and portable, and can be used over nearly any type of substrate. A “must have” for the coating failure investigator. The Tooke gauge destructively reveals the thickness of each coat in a multiple coat system (up to 50 mils thick). An incision is made through the coating layers down to the substrate. The incision is then magnified through a 50X ocular containing a reticule. Depending on the tip no. that is used to make the incision, the number of reticule divisions is converted to mils, microns or millimeters using a conversion table. The presence of mill scale, rust or voids in the coating layer cross-section may also be revealed. The Tooke Gauge is sold complete with three cutting tips (1X, 2X and 10X), AA batteries, spare light bulb, allan wrench, marker and instruction booklet all housed in a durable leather carry case equipped with a shoulder strap. The gauge conforms to ASTM D4138 and is available in lightweight plastic (Model OG214) or aluminum (OG212). The optional Microgroover is used to create the precision V-groove on pliable substrates like rubber, which often deform when conventional cutting tips are used to create the incision. Made in the USA.