Hastings Triplet Magnifier, Power 10X, Diopter 40D, Focal Distance 1 in, 2.5 cm, Lens Diameter 15.8 mm, Case Nickel Plated, Swing Away, Features Incorporates 3 Separate Glass Lenses Bonded Together to Form a Compound Lens, Very Distinct Magnified Image Without Distortion, Lens Glass, Overall Length 5/8 in