Perhaps they could improve the product by using stronger higher quality metals. To put it simply at the moment this is the best model that KZ has made yet. If you purchased the 32GB, the serial will begin with HX432 and the 24 will read HX424. I’ve ordered a size 6 but unfortunately had to order them in a different colour, smaller sizes are not available in the wine. Il pacco è arrivato in tempi rapidissimi. The button options could have been better for switching between Bluetooth devices but its all manageable. I wear a size 22. I didnt use the straps it came with, but instead used automotive ratcheting straps because my trip involved expressway travel at 70-80 mph, and the straps it came with didnt sit well with me. But you wouldnt be able to tell unless you felt them. Not sure how to get ahold of the manufacturer or the seller, but I would like to exchange these for a brand new pair.