I'm writing this review so others can see exactly what size this vacuum hose actually has, as Revain doesn't list it. The inside diameter is 7/64" and the outside diameter is about 1/4". I ordered it based on what others have said in the Q&A and found it it's too small for my small block Chevy Back to the drawing board, I can't fault the product and have ordered other hoses from Gates and found them to be excellent, this one is also made in the USA.