New membrane technology tightens the natural pores in the bladder to improve pressure retention. This technology is specifically designed to repel the air mixture molecules. Spalding Never Flat™ basketball holds air 10 times longer than traditional basketballs... resulting in consistent rebound height for at least 1 year. Proprietary Nitroflate™ molecules are injected into the ball, forming protection against air seepage. Specially designed valve eliminates leaks & keeps dirt out.