The Extreme Max Clean Rig Spacer allows for a clean and professional-looking installation of your 2.25" Ram Ball Mounts or any other marine electronics with a 3-11/16" (3.68") mounting base, including depth finders, GPS and more. Each Clean Rig Spacer is pre-drilled to fit standard mounting patterns. Due to the wide variety of surfaces and equipment the spacer may be used with, mounting hardware is not included (Extreme Max recommends #10 stainless steel hardware). For smaller mounting bases, see Extreme Max 3002.4561 Clean Rig Spacer for mounting bases with a 2.5" diameter.