Two phone grippers for added stability in harsh conditions. Accepts phone and mini-tablets up to 4-3/8” wide (110mm). Anodized aluminum construction and soft touch grippers can be adjusted in any direction to ensure they do not interfere with buttons. COMPRESSION RING included for eyepieces from 39mm to 60.75mm in diameter. (Optional Small COMPRESSION RING set available for eyepieces less than 39mm for sale HERE)