As simple as it sounds, I used two 4" strips of velcro (the rough side, not the fuzzy side) placed an inch from the sides running lengthwise on the box. My box is heavy enough (single 12") that just the carpet to carpet friction held it most of the time, but some turns would cause it to slide. I went with the velcro and the results are amazing. I just finished my suspension so 50 mph turns have become more common, and the box doesn't budge. Using the two small strips makes removal of the box simple too as it is not too much sticking force, just enough friction to keep the box from sliding. Hope this helps.