Optically Worked Double Convex Glass Lens, 75mm Diameter, 1000mm Focal Length Material_Brass holding pH stable at 25

holding pH stable at 25 degrees C for calibrating meters and electrodes at the standard low-acid reference point

Plastic-bodied wave apparatus with eccentric discs that drive metal rods up and down as the handle turns

Compares 2-

and aluminum at a shared 0

Chrome-plated 60mm reading magnifier extending to a 20cm focal length

Optically Worked Double Convex Glass Lens, 75mm Diameter, 1000mm Focal Length Material_Brass holding pH stable at 25Designed for parallel beam refraction work, this 75mm double convex glass lens at 1000mm focal length runs at f 13, near collimated for astronomical analogue and long throw projection setups.