SPI Supplies Brand Linen Tester Metal Frame 7x
These collapsible and folding metal frame pocket magnifiers, commonly referred to as "linen testers", are popular with science teachers because of their low cost and high durability and also their resistance to moisture making them appropriate for outdoor use. Plastic frames are not for everyone since they lack the higher precision of the (somewhat more expensive) metal frame equivalents, either in the PEAK® or SPI Supplies® brands.
- Plastic linen tester, 7x
- Outside base: 1.6875 x 1.5625" (43mm x 40mm)
- Inside measuring area: 0.75 x 0.75" (19mm x 19mm)
- Height: 1.75" (44.5 mm)
- Housing made from black molded plastic
- Fold flat to fit in pocket
- Very light weight
- Economical (ideal for class room use)
The magnifiers with the plastic frames are recommended for those using them in laboratory settings where they could be exposed to corrosive vapors or even outdoor use (since plastic won't corrode). They are also lighter in weight than their metal counterparts and also, being plastic, won't set off metal detectors at airports or other security checkpoints.
Scales in both inches and millimeters are etched on the inner faces of the viewer's base.