Cortex Plug Hidden Fasteners - for Azek Acacia -350 Plugs & Screws for 100 sq ft. of Decking

These are difficult and time-consuming to install. Even with an impact driver, the heads tend to strip. I think this is due to the "reverse thread" on the top portion of the screws, the purpose of which is to cut a nice clean hole for the plugs.Note that they are also NOT STAINLESS STEEL, which you might expect to see for this price.I highly recommend pre-drilling.Installing the plugs is pretty labor intensive; for really good results, you need to try to pick a plug that matches color shade fairly well (color varies across both the boards and the plugs) and align the grain before hammering in.But once installed, and especially after the plugs and decking weather together for a couple of months, the plugs really pretty much disappear. I actually have trouble seeing them on my deck now, even down on hands and knees looking for them.