When high performance is the goal, OakleyUs SI Flak Jacket XLJ Sunglasses can help you meet it. These sport inspired sunglasses feature a half-jacket O Matter frame that maximizes your visual field, while Unobtainium earsocks and nosepads provide a non-slip fit even when damp. Base High Definition Optics (HDO) lenses deliver unbeatable light filtration and distortion reduction, giving you superior visual acuity in bright light conditions.