Used in a social club for adults for games and basic practice. Not used for knocking. Temperature numbers are 2, 3, or 4. A few other brands are mixed in, but they are better than the shuttles in the title. (Certified balls prepared for official matches) Regarding these shuttles, due to the price increase of AEROSENSA, our club switched from AEROSENSA 400 to these for game use, and the feel and durability are quite similar. I will discount the shipping cost for bulk purchases, so please contact me.