The Reichert TONO-PEN® XL Applanation is an easy to use, portable, hand held instrument which provides fast and accurate IOP readings comparable to the Goldmann Applanation Tonometer. Utilizing micro strain gage technology, and a 1.5mm transducer tip, the Tono-Pen gently contacts the cornea, and displays the average of four independent readings, along with a statistical coefficient. Sanitized Ocu-Film™ tips covers are used to minimize the risk of cross contamination. Portable unit for measuring intraocular pressure Documented accuracy Easy to use, easy to handle Results in seconds Display of average readings and coefficient of variance Sanitized tip covers Battery power Specifications:   Weight: 2.25 oz. (64g) Dimensions: 7 1/4" x 1" x 7/8" Transducer: Micro Strain Gage Range of Measurements: 5-80mm Hg Power Source: 2 Ocu-Cel XL Batteries This pack/kit Includes: Tono-Pen XL Tonometer Carry Case 1 box of Ocu-Film Tip Covers 1 pkg. Ocu-Cel XL Batteries Instructional Video and Manual