RockShox Monarch RT3 Rear Air Shock Designed for XC, All-Mountain applications. Features the extremely durable Solo Air spring system. The positive and negative air spring chambers are simultaneously filled to equal air pressures through a single Schrader valve. Features Sag Gradients to properly set sag. with this feature, sag percentage gradients are provided on the shock making perfect suspension setup simple, easy and accurate. Features external rebound and 3 position floodgate switch Available in various compression tunes which are specific to your bike's leverage ratios. High = 2.8+, Medium = 2.4-2.8, Low = &lt;2.4