The antenna stud mount acts as a bridge between the antenna and the coaxial feedline.  Accordingly, it needs to allow for efficient transfer of your transmitted and received signals to and from the transceiver.  If the stud mount doesn't perform that task efficiently you end up with unneeded loss.  And if that isn't enough, the stud mount must be strong enough to withstand all of the stress placed upon it from an antenna that is subject to severe wind load and vibration.  Instead of inexpensive aluminum, FireStik uses chrome plated machine brass.  Instead of 9/16" (14mm) hex-stock, they use 5/8" (16mm) stock.  Instead of ABS or inferior plastic insulators, they use nylon.  Instead of cadmium plated hardware, they use stainless steel.  Furthermore, their heavy-duty 3/8" center shanks can mean the difference between trouble free use and lost antennas.  The K-4 stud utilizes ring terminal connectors (supplied) making it compatible with non-PL-259 terminated coaxial cables.  In a typical installation, antennas with 0.600" (15mm) of exposed threads can be used without the fear of bottoming out before proper tightening is accomplished.  The K-4 can be used in any mount or mounting surface with a 1/2" (13mm) hole.