Photoflex adjustable reflective Umbrellas were already the most versatile photographic umbrellas available today; and now they're even better. The new andimproved umbrella line includes ribs and strut pivots that are now made from a fiberglass composite, which is not only stronger, but also offers better resiliency and durability than steel or aluminum. This new design feature allows for almost carefree handling, all but eliminatingdamage caused from over bending delicate steel tube ribs. All umbrella center poles are extruded and closed off at the base (vs. folded, hollow tubes, like many other umbrellas, that are easily bent and dented) adding to the durability of the Photoflex umbrella model. Silver interior for maximum light reflection. Four moveable ribs make this umbrella adjustable; alter the shape of the umbrella. Can be used for strobe or hot lights. Also available in 30" (UM-ADH30). Shaft diameter is 8mm. Umbrellas have a 3 year warranty.