So just a heads up for other people out there who are using frio cold shoes. I was shooting the other weekend and managed to knock my flash off the lighting rig. I was a little surprised to find this since it was all pretty secure but I was reading on the frio website that they are actually designed to break under heavy loading, its in the FAQ sections, while it most situations it probably is a good thing eg. close to the ground so your hot shoe doesn't break, in mine it actually caused the flash to take a 10m fall.
So basically the frio broke once heavily loaded and sent my flash flying. I'll continue to use them, I'll just be securing the flash using other means not just the cold shoe alone.