The double ball adapter is connected by an aluminum alloy rod. TPU over-molding ball head, non-slip and wear-resistant Widely used on bike & motorcycle phone holder, navigation brackets and other electronic equipment mounts 1'' ball head compatible with RAM Mounts B size double socket arm, 17mm ball head suitable for 17mm swivel ball mounting pattern device mounts Brcovan 1 inch ball to 17mm ball adapter. The double ball adapter is connected by an aluminum alloy rod. TPU over-molding ball head, non-slip and wear-resistant.