Have a look at the possible modes of this leash.
1. Use it like a loop. One end of the leash should be attached to the O-ring and the snap hook should be attached to the collar. Wear the loop on your shoulder. Keep in mind that the O-ring should be in front of your shoulder.
2. If you want to make the leash shorter, attach 1 end to the O-ring stitched closer to the other end.
3. If you are going to the supermarket and you cannot take your Bullmastiff with you, you can tether your dog.
4. Make a 3.25 inch Leash and then grab the floating O-ring and slide it to the end of the leash opposite the clipped ends. Now bring the O-ring back to the clipped end essentially folding the leash in half. Clip the floating "o" ring using the same clip that is attached to the fixed O-ring.
5. If you need your hands to be free, wrap yourself with the leash and attach the free snap hook to the floating ring.
6. Do you need to walk two Bullmastiffs? Attach snap hooks to the collars and grab the leash in the middle.
7. You can use the leash as an ordinary one.