There are 3 different types of RockNobs to choose from: Granite, Moab, and Timpanogos.  The Granite RockNobs are found in Little Cottonwood Canyon near Salt Lake City, Utah.  The Moab RockNobs are weathered sandstone rocks found in the deserts of Utah.  And the Timpanogos RockNobs are found below Mount Timpanogos around the ancient shorelines of Lake Bonneville.  Each RockNob has their unique lizard petroglyph carved into the stone and is colored black on some of the lighter stones for better visibility.

Before you place your order for RockNobs, you must determine the style of RockNob you want, the size of the RockNob you want, and the thread size of your shifter.  There are 2 sizes of RockNobs to choose from.  The diameter of the "normal" size is about 2 1/2 inches and the diameter of the "large" size is about 3 1/2 inches.   If you have big hands or just like to have a big knob, you may want to order the "large" size RockNob.  I ordered a "large" RockNob for the transmission shifter and a "normal" one for the transfer case.

There is a great thread sizing chart on their web site (www.rocknob.com) which shows you how to measure the thread size and pitch of your shifter.  There is also a printable thread chart if you wish to use it.  I kind of cheated and just grabbed my tap and die set to see which sizes I needed for the transmission and transfer case.  I guess you could also thread a nut on the shaft or thread a bolt into the shift knob to determine what the thread size you need.

Installation of the RockNobs is really easy and only takes a few minutes.  Each RockNob is supplied with jam nut so you can align the rock in a comfortable position and lock it in. 

NOTE:  Do not thread the RockNob all the way in especially if you are installing a Moab RockNob.  Sandstone is weaker and more brittle than normal rock and it can crack if the shifter bottoms out.  Always use the jam nut to lock the RockNob in place.  However, the new generation RockNobs have an insert near the top of the threads that will indicate when it is time to stop tightening the knob.  When it becomes physically harder to turn, it is time to loosen the RockNob to the desired position and tighten the jam nut.
 

Remove the old shifter.

Install the supplied jam nut.

Install the RockNob and tighten up the jam nut.

RockNob's unique lizard petroglyph.

Transmission and transfer case RockNobs.