magnetic mount so it can fit most any of them
u-tube link to video showing what it is
http://www.youtube.com/watch?v=1d2WIXwW9w8
you can buy both hat and lens here
http://www.hatcams.com/hatcam_products.html
buy just lense here cheaper (b&h photo)
http://www.bhphotovideo.com/c/produc...etic_Lens.html