Burris Knob Synergy� is a revolutionary modular turret system designed to give shooters the flexibility they've always wanted. Now featured on the next-generation Fullfield riflescopes Knob Synergy lets you seamlessly swap between different elevation and windage knob styles so your scope adapts to your mission not the other way around. - From hunting the backcountry to dialing for steel at distance Knob Synergy puts control in your hands. Upgrade your knobs not your scope. - Knob Synergy Advanced Exposed