Hammer Blue Hammer Bowling Ball The Blue Hammer is an iconic throwback in performance ball technology By combining a re-engineered Vibe core shape with our new Performance Urethane coverstock, were introducing a ball that rolls like the old-school balls without actually being the old-school stuff This new spin on older ball motion brings the control of yesterdays balls and the performance of todays stuff to the lane for Hammer! Color: Blue Core: Modified Vibe Core Veneer: Performance Urethane Surface: 800 Abranet, 1000 Abralon, 2000 Abralon, 4000 Abralon RG: 2