The original also included A/B switching at the output and a simple loop, so I've included a simple A/B wiring configuration on the layout in case anybody fancies including that too. Adapt this with your favourite switching method if you also want to include an A+B option and add a true bypass loop if you want one.
I think this dates back to the 70s or 80s and so I can't find any manufacturers info about the pedal but did find the following information:
The Rivera brand is most famous for its very high quality amplifiers. It is offering new effect pedals these days but this one dates back from the 80's. These days boosters, loopers and A/B boxes are quite popular and Paul Rivera was quite a precursor by offering all three functions into one pedal. This buffer came on the market in many disguises: PMP buffer E945, PMG buffer E945, Rivera Buf IV and V. It is battery or mains powered and has a heavy and durable diecast chassis. Rivera also offered simpler versions like A/B boxes or simple loopers, and even used the box for its M-series and S-series amplifiers' footswitches.
The circuit of the E945 is very simple with a single op-amp taking care of the buffing and boosting duties, while the loop is post-buffer/booster. The pedal works really well and the amount of ultra-clean boost is quite staggering with an internal symmetrical supply of +/-12 volts. This E945 is ideal with a twin channel Blackface/Silverface amp or with a two amp setup giving a pseudo 4 channel rig with one simple pedal.