Is this a 1/2 inch to 3/8 inch conversion? If so, how long is the bolt?

The 6007 brass terminal bolt is designed for side terminal batteries (75, 78). It is used to attached the side terminal to the battery (3/8"-16) leaving the opposing threads (5/16"-18) exposed; to add additional 12V accessories to the battery. The 3/8" side is .38" long and the 5/16" side is .50" long total overall length is 1.54." We have updated the product to include this information.