no identifying words or numbers on these items at all

I am looking for some roller wheel assemblies for a CURVED shower door. I have a shower unit that's 8 years old, brand unknown. It is a corner unit with TWO sliding front doors. The opening is in the middle of the unit, meaning the doors open away from each other, and close together. They hang by roller assemblies and the left-hand door is more or less just hanging now at an angle, as the rollers are not functioning or broken altogether. The wheels on the rollers are 7/8" diameter. I have attached several pics for you to help identify what I am needing. There are TWO top rollers and TWO bottom rollers on each door (four total on each door) though can see the top rollers are very different from the bottom ones. I can sent additional pics of needed but your site only allows me to attach a max of five. Thanks for your help, Mark

Hi and thanks for researching this for me...the part you showed me looks very close...it's not perfect, but I'm thinking it may very well fit, as I suspect these don't need to be a "perfect" fit, as long as they mount properly and the rollers are at the correct angle to fit in the tracks, and it looks like they are.
I see that each kit of the part number you gave me has ONE top and ONE bottom roller, so I will go back to your website and get these ordered. Again, thanks for your help. IF THESE DON'T FIT, what are my return options?