The difference between American rugby and English rugby clothing

Two sports, to put it bluntly, except for using a ball (both are rugby style, very similar, but still different)
The number of people, venue, equipment, sports methods, competition rules, and so on are almost all different
As for jerseys, British style: The traditional top is a polo shirt with a collar and shorts with thick cotton on the sides (In recent years, tight elastic clothing has been recommended.)
American style: The top is a round neck or V-neck wide jersey (for wearing shoulder or chest shields), and the bottom is knee shorts (for wearing knee pads)