I recently bought a used surefire scout weapon light from an individual that claimed he bought a bunch of them surplus. I paid him 20.00 dollars and put batteries in it and it worked. I am new to SF. I guess you can modify these lights with diiferent heads and pressure switches? I guess I would like more info from some experts. I plan on putting it on a sig 556. I also told this lady I would like to by 2-3 more she could get them. What does a good used SF light sell for. I realize this is probaly an obsolete model, but it still works fine and just shows wear on the paint job.