AV Cart side hanging bins

I use an AV cart as a mobile work station and realized that if I have my laptop, mouse and some other items on it, space is pretty limited.  Made this so that I can have some bin style storage on the side of the cart.  There is a mount that attaches to the cart and then each bin is a module style component that slides into a slot to be secured.  The bins I have made are a cup holder (for either side), pen/USB drive holder, misc bin and a phone holder that I am currently revamping since a good bump will knock my phone off.  More modules to come.