The ring gear has 43 teeth and the pinion gear has 9 teeth (43/9 = 4.78). Includes the ring gear, and pinion gear with bearing and crush sleeve. This is everything a transmission or rear end shop will need to install this gear set in your differential. The current offering is exactly the same. This gear will provide increased acceleration over the stock 4.10 ratio, but at the expense of decreased top speed (max 145 mph or so with this ratio).
My research suggests that 4.44 to 4.62 gears are well liked by the S2K community for road racing, with some enthusiasts going for the 4.78 for maximum acceleration. Please do your own research to be sure this ratio will be correct for your situation. Thanks for checking this out, and good luck. The item "Honda S2000 Mazda RX-7 LSD 4.78 Differential Racing 7 Ring and Pinion Gear" is in sale since Saturday, August 22, 2020. This item is in the category "eBay Motors\Parts & Accessories\Car & Truck Parts\Transmission & Drivetrain\Differentials & Parts".
The seller is "aardvarc" and is located in Bonita, California. This item can be shipped worldwide.