W-R135. This inexpensive, high quality, hand held tester is the ideal instrument for general surface roughness testing. This extremely versatile gauge is suitable for testing a wide variety of materials, boasting a large measuring range and easy-to-read, digital display. Features: Ra and Rz parameters, switchable display. Adjustable tracer also for 90 or 180 measurement plane. Standard cut-off of 0.25mm, 0.8mm and 2.5mm, adjustable to 1, 3 or 5 times. Large measuring range suitable for most materials. Piezo-electric pickup stylus for external surfaces (diamond tip for latest ISO standard). RS232 Output. Accuracy to DIN4772 Class 3.