Geller Magnification Calibration Standard, Retainer Ring
Why is a retainer recommended?
Retainers for the MRS-3 and MRS-4 help protect the standards from handling damage (please note these retainers are not for the MRS-5). If handling the MRS-3 and MRS-4 without a retainer the tweezer arms will contact the standard which is made from highly stressed fused silica. Small chips will occur working their way into the pattern compromising its usefulness. With the retainer tweezers contact the metal or the glass slide without touching the standard.
We can also mount the MRS-3 or MRS-4 on stubs for particular instruments such as the 1” pin type or 1" cylindrical with or without 4mm thread on the bottom for Hitachi instruments. If we are to recertify the standard the MRS-SEM/R must also be ordered. The MRS-SEM/R is screwed to the top surface of these mounts.
We have had many MRS-3 and MRS-4 returned to have retainers added. Please consider carefully before ordering without the retainer. In some cases it is the correct decision, especially if size and space are issues.