When applied to spoke treads, Wheelsmith Spoke Prep compound does two things. It lubricates the spoke thread/nipple interface when the wheels are being laced and then locks the spoke and nipple once built. By locked, we mean that the poke and nipple are secured so the spoke will not unwind during use. You will still be able to tru your wheel and remove and replace worn or broken spoke or nipples.
These are sold in twin packs with the same compound, just different colors so you can distinguish between different gauges (diameter) or lengths. This spoke prep has been around for ages and used by many wheel builders.