The linkstar osb-140lsr octabox has a diameter of 140 cm and can be mounted on your studio flash unit with the included speed ring. the studio flash head sits deep in the octabox, which ensures minimal loss of light and provides an even spread of soft lighting. The osb-140lsr is complete with a standard linkstar speed ring, which is compatible with the linkstar ll-d, ll, lf and fs series studio flash units. the linkstar speed ring is further compatible with bowens, studioking, lastolite, jinbei, qihe, and aurora studio flash units. by using an additional speed ring adapter, the osb-140lsr is also compatible with falcon eyes, broncolor, elichrom, hensel and multiblitz studio flash units. to view these speed ring adapter rings, please see the optional accessories tab below. *the following link provides an explanation of how to set up your octabox: how to set up an octabox These softboxes are not suitable for halogen lamps, (such as the linkstar lq-1000), due to the high heat generation of these lamps. the soft boxes from the linkstar lqa series are suitable for such types of lamps.