Double Convex Lens, Highly polished, optically true lens is excellent for physics classroom demonstrations in optics and light refraction, with ground edges, great for physics classrooms, with highest grade, Size: 500mm focal length, Lens measures 3in diameter, 0.1 weight
Marina airline tubing is safe and dependable for use with air stones, air-actuated ornaments and air-driven filters. Designed to fit all standard outlets, the tubing will remain supple and retain its shape. Size: 3 m
AquaClear 20 Zeo-Carb Filter Insert effectively eliminates odors, discoloration and impurities in freshwater aquariums, potent chemical duo prevents the buildup of toxic ammonia and nitrite, designed for Power Fil
AquaClear 50 Zeo-Carb Filter Insert effectively eliminates odors, discoloration and impurities in freshwater aquariums, potent chemical duo prevents the buildup of toxic ammonia and nitrite, designed for Power Fil
Desiccator Plate with Holes, made from high quality porcelain, Contains 6 holes, each with a 1.25in diameter, Great for any school or home laboratory, Can be used in a desiccator to remove moisture from specimen and protect against water vapor, 15cm diameter, 0.3in thickness
Marina Ultra 4-way air control valve allows you to run up to 4 air-driven products. Each valve has flow adjuster which enables you to regulate air output to each devise. The valve is leak-proof and suitable for fresh