No. 235 Eyeglass consists of two convex glass lenses
housed in a strong plastic moulding. Magnification is
x10 and lens diameter is 14mm.

No. 231 Eyeglasses use a single 20mm diameter bi-convex
glass lens in a black moulded mounting. Available in
three magnifications at different focal lengths, x6 @ 1-1/2",
x4 @ 2-1/2" and x3 @ 3-1/2".