Free-Standing Wooden Lens Holder for 50mm Lens Human Anatomy_Human Anatomy Charts & Models Eight aluminum-shank tuning forks tuned

Eight aluminum-shank tuning forks tuned to scientific pitch (C4 = 256Hz) and ranging from 5 9/16 to 7 1/8 inches

Suspends a 20mm solid zinc cube from a spring scale for water-displacement density measurement

the thinnest gauge for mounting the smallest and most delicate insect specimens in permanent displays

Double-pole double-throw brass knife switch

Free-Standing Wooden Lens Holder for 50mm Lens Human Anatomy_Human Anatomy Charts & Models Eight aluminum-shank tuning forks tunedHolds 50mm diameter lenses upright on a free standing wooden base, the simple mount steadying optics elements at bench height for refraction, image formation, and ray tracing demos.