（日本未発売） Storm’s SPEC™ formula was featured on the original PRO-Motion which was excellent at ignoring heavy oil. In fact, it bridged the gap perfectly between R2S™ and NRG™ coverstocks. Since R2X was has been declared on the PRO-Motion Tour, users can easily identify a cleaner glide through the front with no shortage of midlane traction. The Piston Core has turned its fair share of heads, too. It’s a dynamic symmetrical piece that has some very unique characteristics. The channels on the sides of the Piston Core and the large band through the equator displaces its mass in a very specific way. This fits in the mid-range RG value that’s not too high, not too low, and continues to hit on many notes with a lot of bowlers.