The BoatMatesA(R) Swivel Drink Holder is the perfect accessory. Its unique design features a gyroscope motion that will keep your drink contained no matter what weather you may find yourself in. The rod mount drink holder will fit into any Fish-On!A(R) Side Mount (not included) and can be mounted to any flat vertical surface or to a 7/8" or 1" rail with the optional Rail Mount Adapter