i use a steel carabinder thingy from a hardware store. Aluminium and plastic carabinders have eventually failed on me. It nice to know that something is holding you keys secure wenn your not standing. On some pants you will get the problem that the keys won't fit in to you pockets anymore, because they are to far away, but not with the once's i wear. The brass loop on the 5.11 pants is great for this purpose.