Good value 57 mm drop rear calliper brake. Super SLR dual pivot design keeps operating friction to a minimum, improving braking performance. Must be used in conjunction with ST-4600, ST-4603, ST-5700, ST-5703, ST-6700 or ST-7900 STIs for correct leverage ratio. Enhanced brake arch proportions give a quicker linear response and increased power. 57 mm drop. Lightweight aluminium calliper design with tough anodised finish. Toe-in adjustable brake shoes for perfect pad alignment. Durable quick release for fast and easy wheel removal. Comes with 10. 5 mm sunken nut.