The video showcases the product in use.The video guides you through product setup.The video compares multiple products.The video shows the product being unpacked. Are the brass nipples replaceable? Yes. The brass nipples are replaceable, you will need to put an Allen wrench inside the nipple and turn counterclockwise to remove. 2.Will the female jet threads match the 1/2" NPT on my existing shower wall nipples? Yes it would. Where can I get detailed installation instructions? The installation manual has been uploaded to the details page, please check. Is it a constant spray? No,it does have a tiny know on the side that is used to adjust flow just like a spigot on exterior of home they can be adjusted from full flow all the way down to completely off. What do the sprays connect to on the inside of the walls? Connect to the pipe directly.