The Supex Curved Powdercoated Aluminium Roof Rail - Acute Curve (Meaning bigger curve in this sense) is a White powder coated aluminium bar that supports the roll out awnings on the side of your Van. This version with the larger curve suits most applications with just the right amount of curvature to help with water shedding, keep the fabric taught, and improve resistance to flapping in the wind. The rounded top surfaces of the rail protect your awning from wear when the rafter is in place, whilst the large round tightening knob ensures easy adjustment. The one end of the rail features a stainless steel and glass filled nylon moulded rail end which inserts into the provided bracket. The coating increases the strength of the moulding whilst reducing rattling in windy conditions. The other end features the standard tent pole spigot. A less curved version is available (563V) which may suit new awnings with tight fabric or those with less extension.