Rec-mounts Saddle Rail Mount for Gopro&reg; Gopro3 (Rec-b30) for GoPro HD HERO HERO2 HERO3 Come off adapter & 1/4Tripod There's a hole Supports up to rail spacing 43mm-44mm Supports up to rail diameter 6.5mm-9mm CNC Machined 6061 T6 Aluminum Base mount 30g GoPro Adapter 7.5g Total 42g(Including screws) facebook https://www.facebook.com/recmounts http://www.an-y.com/img/rec-mount-catalog3.pdf