Dental Supply Overhead Calculator | TDSC (The Dentists Supply Company)
Calculator Keeper The Educator Basic Overhead Calculator, Manual + Case T1-108 | eBay
See through calculator for use on an overhead projector : r/mildlyinteresting
Scientific Calculator with Projector Model | VWR
Something a little different. An Overhead Projector calculator. By Stokes Publishing Company but built to emulate the FX-300W and a couple of similar models. : r/calculators