They will fit a Gates 3/8" transmission coolant hose when fully open. No problem. Uh, edited. They will fit the hose, but if you have the hose on a steel pipe (like my power steering pump I tried today got).) is a bear for closing. You can't start the screw if you let it come out of the thread. Half an hour or more of struggling with this, the screw finally started with the edge of the clamp on the edge of the hose.