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. The J-Base comes with two Num. 10(5 mm) selftapping screws. Drill a pilot hole in mast, apply silicone sealant or Locktite and screw into mast. 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 mast.