This is my fourth model Fizik Arione saddle. The original and Versus worked great but the Versus X for me had too wide a center channel with too little contact surface area upon which to comfortably sit. The result of prolonged sitting on the Versus X caused irritation (hot spots) in the reduced contact areas. The R3 Open eliminated this issue by having a smaller pressure relief center channel, and I opted for the Large size (142 mm compared to 130 for the standard Arione). These two changes solved the comfort issues and eliminated the hot spots.