1,it will be flashing after hitting. 2,multi-layer construction. 3,the weight is 45g , the diameter is 43mm , wind tunnel is 391. 4,a super-bright Led embedded inside. 5,Du-pont surlyn cut-proof cover. 6,flashing for 6 minutes/30 seconds after hitting (20% difference for the gap of IC inside the ball) 7, battery life, about 40 hours for red ball and about 20 hour for blue and green ball.(because of the different needed voltage)