who here has the best Thai iced tea recipe? and what is the best tea to use as a base?

I saw this video and it prompted me to ask; in the past, when I have made Thai iced tea, I have used a bulk CTC Assam that I have from India but I'm curious if there is another method, or one specific to Thailand? or if people have alternate recommendations/suggestions? (and I also am not sure where to get the sock-shaped thing from this video) - I'm curious about the r/tea community's thoughts!