Marina air stone is ideal for adding accents in any aquarium the air stone diffuses air, creating water movement, increases surface agitation, accelerates oxygen replenishment, release carbon dioxide build-up, Rec
Fluval Water Polishing Pads are uniquely designed to fit Fluval Canister Filters. These extra thick micro-fine polyester pads effectively trap micro particles and debris as water passes through, ideally used when
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: 200mm focal length, Lens measures 3in diameter, 0.2 weight
Pulley Large Demonstration Double, Designed for Classroom Demonstrations, Light-weight, low-friction, and deformation-resistant plastic ensures accurate results, Open to make it easier for users to run pulley cords through them