J-Base™ can be ordered as an option for WindTrak 15. J-Base allows for side, top, or front mounting on most masts, on big boats or dinghies alike. It’s made of glass-filled poly-carbonate, 2″ (5 cm) long. Includes stainless steel set screw and (2) #10 self-tapping screws. Reduces overall weight by 15 grams when substituted for standard mounting base on WindTrak 15.