In hard bottom situations, it may be desirable to place permanent mounting points in the reef itself. We have used a pneumatic drill (1/2” Reversible Air Drill, SKU 98896, Central Pneumatic, HarborFreight.com) and 0.9525 cm (3/8”) diameter masonry drill bit to drill holes in rock reef. The air drill uses a 1/4”-18NPT threaded inlet which is standard for many air tools, but this fitting requires an adapter to attach to common SCUBA 1st stage regulator low-pressure ports, which use a 3/8”-24 UNF thread. These adapters are commonly sold as “NPT to SCUBA adapters”. After drilling the holes, we anchor stainless steel eye bolts in the hole using two-part marine epoxy (A788 Splash Zone Epoxy, Pettit, Rockaway, New Jersey, USA). Stainless steel worm-drive band clamps can then be used to anchor the OWHL housing to the eye bolts while being sure to confirm that the OWHL will not rock or shift once fastened down (Figure 37).