Use these replacement parts for all Davis Windex Wind Indicators.J-Bases3125 J-Base for Windex 10 Sport: Standard with the Windex 10 Sport, this J-Base can be ordered as an option for Windex 15. Allows for side, top, or front mounting on most masts, on big boats or dinghies alike. The J-Basecomes with two #10 (5mm) self-tapping screws. 2"L with 1 3/8" hole centers (35mm). Installation of J-Base can also be accomplished by tapping the mast for 3/16" (5 mm) machine screws or by using epoxy putty to affix base to the mast3155 J-Base for Windex 15: This optional mount for Windex 15 provides more versatility and reduces overall weight aloft by 15 grams when substituted for standard Windex 15 mounting base.Replacement Vanes3101 Replacement Vane for Windex10 Sport1311 Replacement Vane for Spar Fly3151 Replacement Vane for Windex15Reference Tab Assembly and TabsR3152 Reference Tab Assembly, complete with two Reference TabsR3150C Two Reference Tabs onlyAdjust tab arm angle to match upwind performance:55 for boats with good windward performance60 for normal ocean racers65 for normal day cruisers