The RS solar cell module was designed to fit into perforated circuit boards or breadboards for electrical experimentation. It is shown in figure 7.10 of The Solarex Guide To Solar Electricity 1979. The solar cells would have been manufactured by Solarex due to the chevron grid pattern on the surface and integrated into their packaging by RS.
Original image donated by Anthony Skelton, edited by MOSE. Object apart of the Anthony Skelton private collection.