Industry Nine Hydra Hub End Caps Interchangeable end caps have changed the game. No longer do you have to buy a new wheelset because your new frame or fork has a different axle standard. You are currently looking at interchangeable end caps for Industry Nine's Hydra front and rear hubs. Features End Cap Options:Front 15mm Front 15mm Torque Cap Rear QRRear 12x135/150mm Rear 12x142/148/157/177/197mm Rear 12x142mm Micro Spline Front, Center Lock 15mm Front, Center Lock 15mm Torque Cap Rear Center Lock 12x148mm Rear, QR Micro Spline | Industry Nine | Hydra Hub End Caps Front 15Mm