Navisafe Clamp-On Rail Mount Fits On 1" 1-1/4" Rails [920-1]Clamp On Rail Mount Fits On 1" & 1 1 4" Rails Designed to allow secure mounting of the Navilights with magnetic base to the bow pulpit or stern rail. Examples of Usage: The Clamp on Rail mount easily attaches to the bow pulpit and can safely hold for example the Navilight Tricolor. In a nearly center position it may be used in its BiColor mode, otherwise it is recommended to use two Clamp on Rail mounts, each equipped with a Navilight Tricolor showing