I had to hammer it straight and mount it crooked, but you can’t tell when hung. I can move freely and they stay in my ear quite well. I thing think the only difference is that the S-500 types are moisture / sweat resistant. I loved it and would be buying another one so that I can have total four wireless mikes on the set. Received earlier than expected even tho package was delivered to the wrong person. Sibilance. Even if I could I h no idea what they mean. Well done JBL! One piece of advice, please station it on hard flooring not on carpet as it has vacuum pads on the foundation to hold up and does not work on the carpet flooring. Im from the Philippines and i think the 4 days delay in delivery can be considered given the current circumstances (COVID).