? Pack of two. ? The 1.5'' ball mount base compatible with RAM Mounts & BRCOVAN any C size 1.5'' ball double socket arms. Work for other devices with 1.5 inch swivel ball mounting pattern. Compatible with Garmin devices. ? The round plate made of 6061-T6 aluminum alloy material with CNC machining and iii grade hard anodized surface for durability and reliability in the most demanding environments. TPU over-molded ball head, non-slip and wear-resistant. ? The ball mount consists of a C size 1.5'' TPU ball connected to a 2.44" round plate. The round plate features industry-standard AMPS hole pattern and with pre-drilled holes.