Check the listing for details. Troll-Master Adjustable swivel base for CANNON downrigger w UNI-TROLL mount base. Condition: New. Listed at 139.99 USD. Troll-Master AR-1021Heavy duty universal adjustable swivel base with cannon's UNI-TROLL mounting base.This is COMPLETE mounting system for your CANNON downrigger! This fits UNI-TROLL models manufactured prior to 2013 Troll-Master AR-1021Adjustable downrigger base is designed to accept Penn© or Cannon© downrigger mounting plates. The base rotates a complete 360° circle of rotation and locks in 36 different positions allowing you to pick virtually any angle for your downrigger. This feature provides effortless re-positioning of the downrigger boom inboard for rigging, docking or towing. The fact that this swivel base allows for installation of two leading downrigger manufacturers provides fisherman with ability to switch from manual to electric or from one brand to another without any additional investments or re-rigging efforts.The base is brand new, all stainless hardware required for installation is included.