Features: A universal rail-clamping base, designed to fit square or round tubing from 3/4 inch to 1-1/4 inch diameter. This rugged base is made from extruded aluminum, an aluminum ball, and includes stainless steel hardware. The Cradle (UN-198) comes with four grip fingers and one stop finger, which are capable of being positioned in any of the eight slots on the body. Rubber pads for the grip fingers and stainless steel hardware are provided. In the short direction, the grip fingers are adjustable from 1-1/2" to 3-1/4", and in the long direction, the grip fingers adjust from 4-1/2" to 5-1/2". For larger devices, the finger may be left out at the top allowing the device to overhang the cradle base. Like our other products, the SH-228 is produced for use in aviation and marine environments where being compass compatible and corrosion resistant are important.