Rugby Balls Size. Adult rugby is played with a size 5 balls, youth rugby (ages 7 to about 14) use size 4 and the littlest ones, roughly under age 7, use size 3. Grip. Some balls are grippier than other because of the amount of rubber in the mix that makes the outer shell of the ball. Some of the grippier balls are the Mikasa Kick Off and the adidas balls. The higher end the ball is, the longer the grippiness lasts. All the balls we sell have good to excellent grip. Weight. All the size 5 rugby balls weigh about the same. The Mikasa Kick Off and the adidas balls are a bit lighter which is a nice feature for kickers. The ClubPRO Pass Developer is a weighted training ball to helps develop your passing strength and is not meant for regular play and should never be kicked. Inflation. As you inflate rugby balls, air will leak out from the ends until the internal rubber bladder is completely inflated and seals the seams of the outer shell. Once properly inflated, they will gradually lose air over time. Grip Durability Bounce/Flight Value adidas Torpedo X-Treme Excellent Excellent Excellent Excellent adidas Torpedo X-Edition Excellent Good Good Excellent Mikasa Kick Off Excellent Excellent Excellent Excellent ClubPRO Good Excellent Good Excellent Specialty Balls (Internationals, Shamrock, Stars & Stripes, etc) Good Good Good Good ©2009 BALL'S OUT! Rugby Goods. All rights reserved.