The RTD-210 by Starr Instruments is an advanced surface roughness tester that provides the user with comprehensive testing capabilities. 

It is designed to allow testing on almost any surface, including difficult to access samples sich as internal bore and curved surfaces.  

The separate motor drive unit is attached on a 1 metre long USB fly-lead. This is to allow user to freely position the measuring sensor (stylus pick-up) on both internal or external bores of small diameter pipe or tube, stepped gears, o-ring grooves and recessed notches. 

The RTD-210 uses a highly sensitive, diamond-tipped stylus sensor that accurately traces the surface, measuring the vertical deviations from the centre line. It is able to display the results in many parameters including Ra, Rz, Rq, Rt, Rp, Rv, Rsk, Rmr to name a few.  The results are clearly shown on the high resolution, colour touch-screen LCD; including the waveform trace of the test sample and automatic conversion to another parameter.

Results can be saved to the 100 record internal memory and managed with software or downloaded via Bluetooth to a free Android APP. (no iOS version available at this time).


  • 3.5" Full colour graphic LCD Touch Screen
  • USB communication and charging
  • Wide measuring range ±160µm
  • 22 Advanced roughness parameters
  • High accuracy inductive, diamond stylus detector / pick up
  • Separate stylus drive unit and fly lead for increased accessibility
  • Adjustable height stand to fine adjust stylus positioning for precise measurement
Standard kit includes: main display processor unit, stylus and motor drive unit, height adjustable stand, touchscreen stylus, USB cable and mains charger, calibration certificate, Ra calibration specimen and specimen holder.

There is also a range of optional styluses that can be used to extend the testing capabilities of the unit and allow measurement on curved or grooved/ recessed surfaces and small pin holes down to 2mm. These can be purchased separately, please contact us for details and pricing.
For further assistance please contact us.
Maximum Travel 20mm
Indicating Error <±10%
Variation of Indication better than ±6%
Measured Profile Roughness, Waviness, Contour
Parameter (Main) Ra, Rq (0.005µm~30µm) Rz, R3z, Ry, Rt, Rp, Rm (0.02µm~320µm)
Parameter (conversion) Rq, Rt, Rp, Rv, R3z, R3y, Rz(JIS), Rs, Rsk, Rsm, Rku, Rmr, Ry(JIS), RMax, RPc, Rk, Rpk, Rvk, Mr1, Mr2
Filter RC, PC-RC, Gauss, ISO13565
Sampling Length "L" 0.25mm, 0.8mm, 2.5mm
Evaluation Length (1-5)L
Interface USB, Bluetooth
Power Built in rechargeable battery
Detection Principle Current induction
Stylus Force 4mN (0.4gf)
Stylus Angle Diamond, 90°, 5µmR





Model # kr310

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