I bought this to double up on the chest straps for my 31L PRVKE (an idea that I stole from my Peak Design 25L outddor pack) and it makes a huge difference. Two straps feel more comfortable than just one. My one and only complaint is just how hard these are to attach to the pack. It looks great in the long run, but sliding them onto the rail is a real pain. Don't let that stop you from adding this to your pack, though!

Needed a replacement after I stepped on the buckle of my old chest strap. The only problem is that the part that slides onto the rails on the chest strap has a very tight fit. I had to round over the edges with a knife to make it slide on. Otherwise works great though