Chelsea Filter Magnifier Style_Accessory not only opens small screw-backs

not only opens small screw-backs (18mm) but also large watches

Battery-powered plus a USB cable is included for other power options

For measuring specific gravity

See a guide to magnifiers for the partially-sighted

Weight including battery: 230g

Chelsea Filter Magnifier Style_Accessory not only opens small screw-backsSummary The original Chelsea Filter, as developed at the Chelsea College of Science and Technology in 1934. Do not confuse this with the many copies. Detail Many stones appear to change colour when viewed through the filter. Originally designed for detecting synthetic emeralds, nowadays the Chelsea filter is an invaluable aid to identifying many other gemstones. It can give an indication that you have an emeralds and aquamarines, though not a