Unfortunately, we're unable to provide a precise answer for every speedlite available in the market, as speedlites are manufactured in variety of sizes and shapes. If you are concerned that our larger Pocket Boxes might block your IR beam, we recommend laying out the size of the Pocket Box in question on a sheet of paper, cutting that shape out, and placing it on the front of your speedlite. The Pocket Box Max is 8” x 12” and the Pocket Box Round is 8.5”. If it appears that these modifiers may interfere with your speedlite’s IR beam, then we recommend trying the Pocket Box Mini (which is 6” x 7”).