Don?t ask me about those ?locks?. Most importantly, it is very comfortable to wear even over extended period of time - that is the main reason I brought this. Im extremely disappointed! Half sized up would be a perfect fit and a whole size insured me these will last through the fall but arent too big for her now. Purchased from Amazon Warehouse vendor and the box arrived with one shoe. Cant hear the fan at all. FREAKING. They work great, sound is really clear and loud. Theyve even survived the laundry a time or 2 (Although I wouldnt recommend it :-) )The ear cushions do fall off sometimes, but Ive tried the foam ones in different sizes & they hurt my ears after a while. , especially since the headset is not cheap!