Cooler rack

Hi all. I have a 2014 RZR 800 with the Polaris Lock and Ride cargo box. Recently I saw a rig like mine that had a cooler rack on top of the same box. It was fastened by the 4 "holes" in the box. I couldn’t find the owner to ask him about it. Does anyone have any info on a cooler rack that would fit this box? I’ve looked all over the web and can’t find any. Thanks!