This is the two prong version fuel sending unit for 71 - 73 Cougars and Mustangs. The reason for the two prong, is that this particular year used a ground wire coming off of the sending unit. Cougars equipped with the convenience control package, and the XR7's used a three prong version. The function however is not as good as original but adequate and usually will work for years. If you have an original, often times it's just the float that needs replacing, so don't be quick to discard your original.