The stock gear driven transfer cases are made up of two sections, one provides the gear reduction, or "low range," and the other provides the four wheel drive, or the front driveshaft output. Marlin Crawler, as well as others, sell an adapter that allows us to "stack" multiple gear reduction sections. If you look at the transfer case section of the website you can see pictures of both and you'll notice two essentially identical section at the front with an adapter in between.