Series 4000 sets the standards for performance and appearance in the industry. Series 4000(V-vertical blades and H-Horizontal blades) are all aluminum; and the 4000S models have a steel border and steel deflection blades, stainless steel(304/316) construction is also available in ther 4000SS models. Single deflection is offered in the V4002/H4002 models, Double deflection is offered in the V4004/H4004 models, and a built-in multi-shutter damper is offered in the 'M' models.