This clamp is great, fixes onto the inside of marquee beams effortlessly. Kind of. It's unfixing it that can be a problem, so when you go up the ladder to remove it from the beam after the event, take a pair of pliers with you.
Also, but mindful of the type of eye bolt/bolt you use with this clamp. Accidentally bought some M14 eye bolts that were too long, so when I attempted to close the clamp onto the beam I damaged the thread on both the eye bolt and the clamp. My advice - fit the clamp to the structure first, THEN fit the eye bolt onto the clamp! Then do the reverse when taking it down! Lesson learned!