78mm????2pin?????????????????????????????????????????? I put these all over in my duck/fishing boat. I keep hanging stuff up only to find a pile of jackets and coats of varying weights under it in the morning. It shapes itself to whatever you put in it. Love the feminine springy pink! Not hard to install, you just need to understand the cable, it has a manual handbook. My kids needed to wear headphones for school because of distant leading due to COVID. Excellent headset! (If sizing is a concern, please see my note at the end of this review. Bought 3 more for a total of 4.