Don't be fooled by high priced massage lacrosse balls. Velocity massage lacrosse balls are tested by the Safety Equipment Institute (SEI) in order to meet the standards, set forth by the National Operating Committee on Standards for Athletic Equipment (NOCSAE). Our approved, Velocity massage lacrosse balls are the same quality and softness as other more expensive brands. Our manufacturing facility goes through rigorous testing, in order to qualify to meet SEI requirements. All legitimate brands have to meet the same specifications set forth by NOCSAE. These Industry Standards are for massage lacrosse balls used in official play in Colleges, High Schools, Clubs and Youth Lacrosse across America. The new 2017 specifications are so strict, that there should be almost no noticeable variations between legitimate brands, so why pay more? We use a high quality vulcanized rubber and polish the seams for better handling and ball control. All massage lacrosse balls will lose some of their grip overtime and will become slick. The word that's used is called Greasers. We use 100% pure natural rubber and NEVER use recycled materials. Velocity massage lacrosse balls will keep their grip for a longer period of time. Most yellow balls are used for women's massage lacrosse balls. Lastly, let's not forget man's best friend, Rover. The lacrosse ball is an excellent replacement for the pet store soft rubber toys and tennis balls. They just Don't last. Dogs rip right through them and poof, there goes your purchase. Since massage lacrosse balls are hard and compressed they will last forever, as long as Rover doesn't bury them in the yard. We Don't recommend catching them in the air due to the hardness. Having your dog chase after it and picking those up on the ground or bounce should be great fun for them.