Heavy duty speedring SRTB sustains the weight of TERAD softbox firm and it is recommend to use with large size TERA Softbox such as TERAD 57" (150cm), TERAD 76"(198cm). It is available with a custom adaptor for 7 brands; Aurora/Bowens, Hensel, Elinchrom, Profoto, Broncolor, Multiblitz and Balcar.