An economical, high quality bench set that is excellent value for introductory lens work. Features include: 74cm extruded aluminum bench with push-on plastic feet and large easy to read scale, three-position riders accommodate push-in stems of optical parts, pushing stem in locks rider in position, four 50mm diameter mounted lenses (3 convex, 1 concave), LED-illuminated “F” object, and an opaque screen with scales. This introductory bench set allows the basic properties of lenses to be explored. The optical elements are mounted in robust molded holders that are simply pushed into sockets in the riders. Each ridder can accept up to three elements. The riders slide freely on the aluminum bench until an optical element is pushed in, when the rider locks in place. This eliminates accidental repositioning and allows thee entire lightweight setup to be carried around without anything falling off. The LED-illuminated object is self-contained (powered by an AAA batter – no cables!) and generates bright, clear images on the opaque screen. Four high quality lenses are included, all with 50mm diameter. The focal lengths are +100mm, +150mm, +200mm (all convex), and -150mm (concave).