My grandfather worked for Ralston and through the years has come into many of their collectibles. He recently asked me to look online and see what I could find out about the glass beer stein(s) he has. They are simply glass steins with the checkerboard symbol and an R on the bottom right corner of the checkerboard. I have tried uploading a picture with this message but it keeps telling me the picture is too large no matter how small I make it.
I am unable to find anything regarding this piece of glassware and I'm hoping that someone on this site may have some insight into how I could get more information on the rarity/value of these items? He has 3 in total. I appreciate any information you may have or anywhere you could direct me that I may be able to find out more

There is quite a few on E-Bay, red or black checkered. Are they like a large root beer mug? Or just a large drinking glass? There is also a lot of coffee mugs also. Purina had a lot of advertising pieces over 5,000 item on E-Bay alone so I'm not to sure what he has is that rare.