Possibly just a defective pair? Heard great things about them but for the price the mic working is a must! The keys allow a peice of plastic to slide back revealing the head of the tightening screw. These 3-shelf units are really convenient in that they are actually DESIGNED to stack, with two little wooden stacking pegs at the top of each three-shelf unit. ) If you have stubby toes, these will not fit you well at all. I believe this could have been done better or differently. color was nice. Reason I am not giving a 5 star review is because this is my 3rd one in 3 weeks! Bluetooth is a disaster:When I got my first order, and the bluetooth would disconnect during an online meeting (Microsoft Teams) i thought it was a problem with the one headset so I asked for a replacement. 5 and unfortunately it did not fit my feet nicely. Total waste of money!