Double Concave Lens, 500mm Focal Length, 3" (75mm) Diameter - Spherical, Optically Worked Glass Lens - Ground Edges, Polished - Great for Physics Classrooms - Eisco Labs

Eisco Labs Optical Glass Lens, Double Concave, 75mm Diameter, 20cm Focal Length - Ideal for Top Spinning

Eisco Labs Double Convex Glass Lens, 75mm diameter, 200mm Focal Length

Srate 1pc Optical Glass 100mm Diameter Focal Length -300mm Large Optics Double Concave Lens

Eisco Labs Double Concave Glass Lens, 75mm Diameter, 30cm Focal Length

Sciencent Double Concave Optical Lense 20 cm Focal Length, 75mm Dia

Eisco Labs 6 Piece Premium Optical Glass Lens Set, 50mm Diameter - 3 Double Convex (20, 30, 50cm FL) and 3 Double Concave (20, 30, 50cm FL)

Metal Flip Over Top (Tippie Top) by Gyroscope.com

Lambda Solid Brass, Ruby Tipped Spinning Top

EDC Keychain Spinning Top - Stocking Stuffer. Spins Forever (up to 5:27 min), Self-Balancing, Precision Machined Stainless Metal. This Keyring Fidget Gyroscope is a Unique Gift For Adult Men, Boys

Eisco Labs Concave Glass Mirror, 10cm Dia., 10cm Focal Length