Calibration discs for Gemtest-PGI Magnifier Style_Reader (handheld) it works on nickel providing

it works on nickel providing the nickel hasn't be processed with a coating

Good working distance (enough space to work with both hands on the lower magnifications)

it also gives a wider range of reading

•    Power Off: hold the power/zoom button for four seconds then wait two seconds for it to turn off

Calibration discs for Gemtest-PGI Magnifier Style_Reader (handheld) it works on nickel providingDetails Spare calibration discs for GEMTEST PGI. The Gemtest PGI must be calibrated regularly to ensure it is working properly, especially if the temperature changes. This is not difficult: you place the probe on of the circles and press a button, then place it on the other circle and press a button. The only problem is: if you've lost the calibration discs.