The GLOW LOW PROFILE SPEEDRING 130MM for BOWENS helps the flashtube reach maximum output efficiency and extends the service life of the tube. The 130mm Speedring is used by Glow EZ Lock Octa Softbox, the dynamic eight-sided shallow parabolic shaped softbox, featuring flattering, soft and luxurious color lighting with all the significant advantages of the softbox/umbrella quality. Bowens designed flash heads are an orchestrated balance between the heights of the tube mounted in the base plate of the strobe and the sweet spot maximizing the power of reflectors and modifiers. This low-profile speedring design accommodates the lower tube mounting position found in Flashpoint XPLOR600 series monolights. The shallow mount ring takes better advantage of the Bowens modifier to work with the Bowens design. You get the best bang for your buck for light from your flash, for softboxes with interchangeable speedrings to distribute with the best spread. Without the low-profile speedring design benefit, some of the light and heat produced may be 'trapped' into the collar ring of the mount and output compromised. The extra bit of utilization may make all the Guide Number difference.