BSpeed Stacks Stack Pack - 12 GREEN Competition Cups with DVD, Precision Timer and Mat ReviewbP PP Speed Stacks Stack Pack - 12 GREEN Competition Cups with DVD, Precision Timer and Mat P12 Speed Stacks Competition Cups Specially desighed for performancePSTACKit Precision timer holds and protects cups when not in use.PSTACKFAST Instructional DVD to teach you how to stack fast including tips.PSTACKit Mat - Provides cushioning and just the right surface friction and stability.PSpeed Stacks are the Official Product of the WSSA - World Sport Stacking Association.