![File:Vintage Melcor 400 Electronic Pocket Calculator, Red LED Display, Made In USA, Circa 1973 (15267415081).jpg - Wikimedia Commons File:Vintage Melcor 400 Electronic Pocket Calculator, Red LED Display, Made In USA, Circa 1973 (15267415081).jpg - Wikimedia Commons](https://upload.wikimedia.org/wikipedia/commons/2/2d/Vintage_Melcor_400_Electronic_Pocket_Calculator%2C_Red_LED_Display%2C_Made_In_USA%2C_Circa_1973_%2815267415081%29.jpg)
File:Vintage Melcor 400 Electronic Pocket Calculator, Red LED Display, Made In USA, Circa 1973 (15267415081).jpg - Wikimedia Commons
![File:Vintage Melcor Pocket Scientific Electronic Calculator, Model SC-635, Red LED Display, Sealed Battery Pack, Made In USA, Introduced In 1974, Discontinued In 1975 (16212499963).jpg - Wikimedia Commons File:Vintage Melcor Pocket Scientific Electronic Calculator, Model SC-635, Red LED Display, Sealed Battery Pack, Made In USA, Introduced In 1974, Discontinued In 1975 (16212499963).jpg - Wikimedia Commons](https://upload.wikimedia.org/wikipedia/commons/thumb/0/0b/Vintage_Melcor_Pocket_Scientific_Electronic_Calculator%2C_Model_SC-635%2C_Red_LED_Display%2C_Sealed_Battery_Pack%2C_Made_In_USA%2C_Introduced_In_1974%2C_Discontinued_In_1975_%2816212499963%29.jpg/1731px-thumbnail.jpg)
File:Vintage Melcor Pocket Scientific Electronic Calculator, Model SC-635, Red LED Display, Sealed Battery Pack, Made In USA, Introduced In 1974, Discontinued In 1975 (16212499963).jpg - Wikimedia Commons
![A few Melcor calculators, 1971-1975. Top left, “Gentry,” is prototype/ preproduction. Unit missing label is a model 370. : r/calculators A few Melcor calculators, 1971-1975. Top left, “Gentry,” is prototype/ preproduction. Unit missing label is a model 370. : r/calculators](https://preview.redd.it/208im5lxx9z81.jpg?auto=webp&s=49d40d47cc221816c88724165ef80843bb6e9f5c)
A few Melcor calculators, 1971-1975. Top left, “Gentry,” is prototype/ preproduction. Unit missing label is a model 370. : r/calculators
![https://flic.kr/p/2hijXfq | Vintage Unisonic Electronic Pocket Calculator, Model 1540D, 8-Digit Display, Overflow Memory … | Pocket calculators, Calculator, Vintage https://flic.kr/p/2hijXfq | Vintage Unisonic Electronic Pocket Calculator, Model 1540D, 8-Digit Display, Overflow Memory … | Pocket calculators, Calculator, Vintage](https://i.pinimg.com/originals/f7/39/3d/f7393da06644a56b2cc8720c5a9e7d00.jpg)