Reed Relay Demonstration Board Subcategory_Entomology Supplies a step up from the

a step up from the 70mm model with extended pole separation that gives field-mapping experiments more room along the magnet axis

12 VDC converter for accessory battery

Used to teach how AC/DC ammeters and voltmeters work

Used as the red-rail partner to the 150mm black 4mm-stackable lead

Hand-painted arterial red and venous blue vessels trace the full systemic and pulmonary circulation across a mounted human figure for cardiovascular teaching

Reed Relay Demonstration Board Subcategory_Entomology Supplies a step up from theDemonstrates electromagnetic switching on a base with 4mm plug connections, where current through a coil closes a separate contact and shows how a small signal controls a larger circuit.