These straps come standard on the Original Kit Bag, Snubby Kit Bag Original Pattern, SAR Kit Bag, and Heavy Recon Kit Bag. On all of the other Kit Bags they are an optional accessory. They don't replace the KB harness, but supplement it. You may want a pair to leave on every pack you carry your KB with.
Using Lifter Straps
Step 1 - Put your pack on over your Kit Bag as you normally would. Install the lifter straps somewhere on your pack's shoulder harness using the black slik clips.
Step 2 - Insert the grimloc into the Lifter Strap
Step 3 - Close the grimloc
Step 4 - Adjust the Lifter straps to your desired height
Step 5 - Loosen the side straps on your Kit Bag