Originally Posted by LasagnaCat

The bottom part of the Puretech strap is roughly .4mm thick... it's really not an issue or a worry running under the pack. You really can't tell it's running under the pack when it's in the car. The 5 inch strap is the right one, and you get a pair for the price. For any other old-timers, yes.. same Puretech that made the straps you may have run on your rc10/jrx2/etc. once upon a time.