Plug-Type Brass Resistance Box, Model B Geology_Geology Charts & Models Nineteen-piece electrostatics kit anchored by

Nineteen-piece electrostatics kit anchored by a gold-leaf electroscope

5 N/m spring constant

the f/3 curvature stretching the focal throw for demos that need the focal point set comfortably beyond the mirror face

25-inch frame with draining pins for post-wash inversion and drying

with banana-plug terminals for optical-bench and physics-demonstration circuit setups

Plug-Type Brass Resistance Box, Model B Geology_Geology Charts & Models Nineteen-piece electrostatics kit anchored byPlug type resistance box with constantan wire coils between split brass contact blocks, providing low temperature coefficient reference values for Ohm's law and bridge calibration work.