Fitment and Product Information. Hot Rod Series 6-Gauge Set – 3-3/8 in. Brandname: Classic Instruments Part Number: HR101SLF Description. Classic Instruments Hot Rod Series gauge sets give tradition a fresh new look! Classic brings back the memories with their Hot Rod Series, a tribute to the early days of street rodding. They offer black and white, easy-to-read pool cue pointers and gleaming bezels–nothing fancy, just straightforward and clean. These precision gauge sets are available in many different prepackaged kits for you to choose from, including those with Classic’s Duals and Quads. WARNING : This product can expose you to chemicals including Styrene, which is known to the State of California to cause cancer.