Apple pie front handguard barrel spacer. Some sanding may be required(but not to much) for it to properly slide on barrel and stay in place. if the spacer is loose in the handguard a small piece of tape will help it fit snug(super high tech). Outside diameter is 1.06 inches and the inner diameter is .750. Just download and slice and slide into the front handguard. Feel free to mess with the inner and outer diameter to fit your needs.
You should be able to see all the modifers.
I made this in Prusa and i don't know how to make it an stl because i used modifers to make it and they wont transfer as STL.