Chelsea Filter Taps & Dies The number in the upper

The number in the upper left corner of the lens plate indicates approximate diopter power

The Foredom S-10802A is a 44-3/8" heavy duty outer sheath assembly designed for use with square drive inner shafts (cables)

For 220/240V use

Longhi and Eid have succeeded in assembling a reference that stands apart from anything previously published on these techniques

Chelsea Filter Taps & Dies The number in the upperThe Chelsea filter is a compact gemological tool used to help identify certain red, blue, and green gemstones by observing characteristic color reactions under filtered light. It is especially useful for spotting imitations mixed into colored stone parcels and jewelry, and for differentiating emerald from common emerald look alikes. Features Assists in identifying select red, blue, and green gemstones Commonly used to detect simulants in colored stone