Rec-mounts Base Adapter for Double [400-double-gp1] 2 lights, mount for light & camera (Type1(no rotation) only REC-MOUNTS Type7 Type9 Type17 Type19 Type21REC-B21 REC-B30 REC-B030 for aluminum reginoid mount. one hand aluminum may loading over, mount will be damaged. Ex.REC-MOUNTS outfront bike mount.fasten screw on bottom. 2 lights. light & wearable camera will be mounted. light adapter of REC-MOUNTS can be mounted.GoPro can be mounted. Garmin(VIRB) Shimano sports camera can be mountedbut may be loose. material aluminumg Type1 no rotation.Type2 one side rotaryleft is the rotary on image but will also be on right side interval60mm need 3/16 inch allen wrench when Type2 tightening of screw cycle catalog(PDF http://www.an-y.com/img/rec-mount-catalog.pdf