But I didnt buy these for sound quality. Before the resistance bands my pull ups were not uniform now i can lift myself completely up. *SN* I also purchased the multi-colored shoe for my husband in a size 15. Beware of this issue - youll have to spend extra time and money on finding proper anchor / screw combination to work for this product. Solid product! Didnt receive either AC5 nor F-4II/skins. I would think in the event you go OTB or otherwise crash and somehow you smash the Bolt and break off the tabs in the mount you have another one ready to go ;) A nice touch for a sub $10 item! fit like a charm. They did stretch a little but not enough to wear for 8-12 hours a day. (technically it serves its purpose and works just fine.