this is the codename for RSL racquets. RSL topline racquets; 1. Diamond X2-Pro (professional?) 2. Diamond X2-AP (Attack Power?) 3. Diamond X2-SP (no idea...) 4. Diamond X2-FP (Fire Power?) 5. Heat 7900 6. Heat 7490 ... .. and others. these new millennium 7 series racquet, you can view from www.rslcanada.com, go to the racquet specifications to view full range.