hi, I appreciate the comment. not referring to the over flow hose clip, that clip is on the outside of the radiator tank, this is a removable clip that clips on the same face as the UH tag but at the bottom of the same side. it is the same shape as the radiator tank face, 1/2 inch wide, bends to form the radiator tank and clips under and into the radiator tank, and has a "O" stamp into it. my car is a 1969 Camaro Z/28 survivor with 37,000 miles on it. I have seen only in picture of other Z/28 radiators that have been restored with there original UH tag and the same tag I am referring to. but can not find any thing about this tag. I will take some pictures of the tags and forward them, thanks again. John