The falcon eyes 16asb-21 mega softbox has a diameter of 210 cm and is almost round in shape. the 16asb-21 provides a large, even spread of light making it suitable for photographing models. the inside of the 16asb-21 is lined with a silver reflective material, which ensures a high return of light and sufficient reflection. In combination with a light boom set, the 16asb-21 can alternatively be used as a flash umbrella. instead of mounting your studio flash unit behind the 16asb-21, the studio flash unit is mounted facing toward the inside of the 16asb-21, and the flash light is softened and reflected by the silver lining (see photo 1). for compatible light boom sets, please see the optional accessories tab below. The 16asb-21 is supplied with a standard falcon eyes speed ring. this speed ring is compatible with all falcon eyes studio flash units except for the falcon eyes ss series. by using an additional speed ring adapter, the 16asb-21 is compatible with bowens, broncolor, elichrom, hensel, multiblitz and linkstar studio flash units. to view these speed ring adapter rings, please see the optional accessories tab below.