Quality, good gloss, bright, tension and muzzle velocity and rebound very good will be good, good rubber band from the exterior flat high degree of good with the core; shiny color, the lighter the color the more crisp, deeper the higher flexibility; pull up the rebound rubber band good is good, as tension size can choose different models or made to wear a cocktail or a rubber band in the group, will increase the power. Rubber band colors that appear dark, no gloss rubber band generally not pull through.