I started to use a walker 2 years ago and bought a tray on-line. It didn't sit evenly and it had 2 holes for cups that were not only the wrong size for any cup but if you were to try to put a cup in it, the cup would be blocked by the bar of the walker. This made it totally useless and lost surface space. I went on line with the intention of telling that company how to make improvements when I came across your ad. How fabulous! It works for holding cups and it comes with a bag that is easy to attach.

I received your walker tray from Amazon today, and I am pleased with the purchase. It fits my Drive Medical Walker perfectly. I will be using it mostly to bring my dinner plates into the living room to sit at my walker and eat while I watch TV in my recliner. I had hip replacement surgery 2 weeks ago and trying to walk with the walker and to carry something is impossible. This will make that easy as pie.
I do have one suggestion, however. You have slots in the tray in what I would refer to as the 'back' edge of the tray. The FRONT is the leading edge of the walker with the wheels on the legs. Hanging the carry bag from these 'back' slots makes it difficult to use the tray as a dining tray. Using the tray on my walker with my laptop would also be encumbered by the placement of the carry bag at the rear.
I may or may not be the only one who feels this way, but it should be an option to hang the bag from either the front or the back, depending on your preference and how you intend to use it.