Rec-mounts Extension Adapter Go-pro, Aluminum Model, 50mm, Set of 2 for aluminum mount. mount of resinoid may be damaged with resinoid base mount. resinoid adapter can be used for tip It may become camera shake by the adapter. do preveiontion for camera shake Simple package no instruction manual facebook https://www.facebook.com/recmounts cycle catarog(PDF) http://www.an-y.com/img/rec-mount-catalog3.pdf