The RAP-B-397-1-201U consists of the RAM Tough-Clamp clamping base and 1" ball compatible STANDARD length double socket arm. The RAM Tough-Clamp includes a 1" ball which can be used to mount a variety of products utilizing RAM's vast selection of mounting solutions. Attach your GoPro Camera, Smartphone, RAM AQUA BOX Pro or similar light weight device on almost any flat surfaces and square rails. Clamping Dimensions: 1. Flat surfaces and square rails from 0" to 1" thick 2. Round rails from 0.25" to 0.75" OD