Quickscrews International Corp  has a removeable Hanger Bolt in Stainless Steel. The bolt combined with their 3" Stainless Steel Compression Washer allows the user to get a waterproof seal on the roof tops. The 5/16-18 hanger bolts are available in 7" and 8-1/4" lengths and can be driven in by our deep socket hex driver. All the solar parts can be viewed on their web site at www.quickscrews.com.