Interchangeable mounting bases fit "2-in 1", Pro Series and Mini Rigger fishing systems. 50227: Flush mount, mounts to gunwale or deck. Easy-open cover conceals fasteners, and elastomeric liner seals water out. When closed, the low-profile, contoured design avoids snagging. 50117/5011W7: Bi-axis side/surface mount can be used on a vertical or horizontal surface or used with the 50127 rail adapter. 50127: Rail mount for use with rails from 3/4" to 1-1/4" in width. For use with 5011 side/surface mounts.