FOR YOUR INFORMATION Below is a list of our Shock Terminology you will see in the catalog Ski Shock (Ski) Shocks on the front of the snowmobile. IFS, AWS, etc.  Front Track Shock (F.T.) The shock on the front of the track suspension. Also called the front arm or center shock. Rear Track Shock (R.T.) The shock on the rear of the track suspension. Also called the rear arm. IFP Shock The shock with the internal floating piston (IFP) in the shock body. IFP keeps the oil and nitrogen separate. Reservoir Shock The shock with an external reservoir attached. Steel braided hoses attach most snowmobile reservoirs. There are two types of Fox reservoirs: Standard Reservoir - the same diameter as the shock body. It is used on earlier Arctic Cat models and some Polaris XCR Special's rear track. C.D. Reservoir - C.D. stands for Compression Dampening. This reservoir is easily identified by its larger size and red knob on one end. Also known as "Clicker" Reservoir. Compression The shock shaft moving into body. Rebound The shock shaft moving out of body.  Dampening The force that resists the shaft from moving. More dampening will add resistance to the movement of the shaft. More compression dampening, the shaft moves in slower. Less compression dampening, the shaft moves in faster. More rebound dampening, the shaft moves out slower. Less rebound dampening it moves out faster. Quick Adjust Front Track (Q.A.) This is the adjustable length shock used on Arctic Cat 440 race sleds and some specials. This shock is easily identified by the adjuster knob on handlebar or console and reservoir mounted on front of skid frame. Fox Air Valve (FAV) The brass "nut" that holds nitrogen in the shock. It houses the rubber "pill" that the inflation needle penetrates to inflate the shock.