Superior version of the classic device for investigating electromagnetic induction. Primary and secondary coils are wound on robust molded formers fitted with shielded banana jacks. The plated iron core has a molded handle for accurate positioning in the coils. The primary coil has 175 turns of 18 AWG insulated copper wire (diameter 34mm, length 100mm, resistance 0.43 ohms, self-inductance approximately equal to 3.1mH). Secondary Coil has three available windings with 500, 1000, and 1500 turns of 26 AWG insulated copper wire. (Usually only one available windings on competing products) (diameter 52mm, length 102mm, resistances 11.5 ohms, 23.3 ohms, 35.7 ohms, self-inductances approximately equal to 490mH, 1.97H, 4.43H). Plated iron core is 19mm in diameter and 165mm long (including handle). Includes activity guide. Shipping weight: 2.25 lbs. Dimensions: 4" x 2.75" x 6.75".