Designed for use with Crestliner's SureMount Gunnel System, the Extreme Max Aluminum Slider Bases place your add-on marine accessories in whatever position is convenient for you. Attach your fishing essentials or other mountable marine accessories to the slider base, placing mounting holes through the slider base bracket instead of through the hull of your boat. The base easily installs into the SureMount rail and may be repositioned quickly with a simple adjustment. Includes four Slider Bases.