Like most good bubble plates on the market, this too is made from copper. The more copper the vapour passes through, the more the copper works to extract impurities out of the spirit.
Bubble cap plates are primarily used to create more reflux in a distillation column. The more plates you have, the more refined the end product will be. As it would have had to be basically distilled in each section over and over to reach the condenser near the end. If you've heard of the triple distilled, that would basically be three bubbler plates for example.
But sometimes its not more is better. For whiskeys, rums and gins for example where you want heavier oil transfer over into the final product the fewer bubble cap plates (within reason) would give you a more flavourful product at the end.
This particular product is designed to be used with the KL36962 - PolyPhoenix - 3 Inch TC Tee or KL36979 - PolyPhoenix - 3 Inch TC Straight Extension depending on your setup wants and needs..