However, using these products with tilt racks proves to be a greater challenge. Most mounting feet on tilt racks require two lag screws to resist the withdrawal forces that can occur at the rear foot. Though there are a number of mechanical flashing products on the market that utilize two lag screws, only a few integrate with selected tilt racks in the SWH industry. Heliodyne, for instance, utilizes the same flashing used on standard plumbing vents to mechanically flash the feet of its tilt racks. EcoFasten Solar's GF2 flashing and brackets provide another option for connecting the rear mounting feet of standard racks directly to the roof. There are a number of collector manufacturers that suggest waterproofing lag screw penetrations by applying a quality sealant to the threads and between the mounting foot and the roofing