Optically Worked Double Concave Glass Lens, 75mm Diameter, 150mm Focal Length Gifts this enlarged Hydra dissection model

this enlarged Hydra dissection model reveals internal anatomy

Engineered with a higher spring constant than a classic coiled novelty spring

Compact metal-box convection demonstrator at 10 by 4 by 3 inches with two glass chimneys

Pairs with the Malvern turbine/pump unit through two basins and shaped glass tubes on a stand

Brass-knife single-pole single-throw switch on a durable plastic base

Optically Worked Double Concave Glass Lens, 75mm Diameter, 150mm Focal Length Gifts this enlarged Hydra dissection modelOptically worked double concave glass lens at 75mm diameter and 150mm focal length, the diverging curvature producing virtual upright images for refraction and beam spreading work.