RockShox Monarch Plus RC3 High Volume Rear Air Shock 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 external rebound, 3 position compression lever Weight: 325g 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. 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