Lad I used to work with had one...he was bald like me but came to work one day with this real neat hair cut...took me a few mins to realise who it was....
These new ones are glued in place but you have to let your hair grow first round the sides then they fade it in....if it's done right it looks really good...as did his...
The wife's hairdresser does them...Mrs asked me if I would do it...I would but only for a 1 off event ....can you imagine the shit you get of your work mates...lol...and to be honest going bald never really bothered me...as soon as I started receeding down the sid