This machine is an evolution of the SRW, combining automatic square roots with the ability to automatically square a number. With the separate multiplier keyboard that was used on all Friden rotary calculators, automatic squaring was a significant mechanical challenge. The number from the multiplier keyboard had to be automatically transferred into the main keyboard before the operation could begin. The mechanism required more room than the standard W-line enclosure would allow, so the bottom plate of the machine was unique to this model, giving an additional .5” height. One of three square root machines produced by Friden, the others being the SRW and RSR.

My sincere thanks to Dr. Robert Baron for the donation of this machine