These bungs are very low profile. Overall length is only .550: long. Thick enough to not warp from welding, Strong enough for most projects, Small enough to not add excessive weight to your project. To use them just drill a small hole ( 11/16" ), place them in the hole and weld them. These have a M 10 X 1.25 internal thread. The od. of the bung is .905" The shoulder diameter is.670" The hat thickness is .200" Shoulder length is .350" long. This is for FOUR pieces. Use them to mount anything you want to tanks, seats, frames, anywhere you need threads to mount most anything. Made from 1018 mild steel.