Spare 500g Iron Hooked Weight with Retractable Hook Subject_Astronomy Alternate-model 75mm double-convex glass lens

Alternate-model 75mm double-convex glass lens at 300mm focal length

Document analysis kit teaches forensic investigation through ink chromatography

75-inch diameter pendulum bob with a removable threaded hook

Thirty-five-component electronics kit extending the Electronics System 1 set with capacitors

Seven-junction copper-and-iron thermopile from four 130mm wires of each metal

Spare 500g Iron Hooked Weight with Retractable Hook Subject_Astronomy Alternate-model 75mm double-convex glass lensCast iron 500g mass carries a retractable hook for suspension from spring scales, pulleys, or beams, serving as a replacement piece for gravitational and force measurement setups.