Portable Digital Voltmeter, 0-20V DC Subcategory_Zoology Models and accessories for combined friction

and accessories for combined friction and inclined-plane work

Single open-or-closed switch on a 4mm-terminal base

a battery-free source of partial vacuum for bell-jar demonstrations without external power

this handle-fitted bicycle wheel lets students feel torque resistance in a spinning mass

holding twelve tubes up to 22 mm diameter for classroom and professional bench setups

Portable Digital Voltmeter, 0-20V DC Subcategory_Zoology Models and accessories for combined frictionBattery powered portable digital voltmeter measuring 0 20V DC at plus or minus 1 digit accuracy on a large LCD, sized to give student bench setups a direct numeric reading without analog parallax.