The Large Daylight Plus 1 is designed for use with large Fresnel lights. It is rated up to 12,000 Watts and diameters from 9" to 21.5 inches. It may also be used with a strobe light, but this is not economical in the long run, since adapter rods would be required for the attachment of a strobe ring; this box has shorter rods.
The extra depth of the Daylight allows the Fresnel beam to spread out and cover the front face more evenly. This extra depth, combined with a fabric that is more heat resistant, makes the box safe when used with a 10K light.
The "Plus 1" designation means the face of the box is removable. Chimera makes different strengths of diffusion material for front face applications. This softbox comes with a one stop diffusion cloth. Additional 1/2 and 1/4 grid cloths are available separately. Substituting a half or quarter diffusion, or taking out the interior baffle will result in more contrast, slightly more light transmission, and less softening of the light.