Racing rad cap 18-22psi with pressure relief lever.& nbsp; These are Stant Lev-R-Vent style racing radiator caps that fit the standard SAE “A” size (2 1/8″ OD 3/4″ deep) filler necks. <span id=”sceditor-end-marker” class=”sceditor-selection sceditor-ignore” style=”line-height: 0; display: none;”> </span><span id=”sceditor-start-marker” class=”sceditor-selection sceditor-ignore” style=”line-height: 0; display: none;”> </span>& nbsp;They inlcude an upper gasket so they are for use on open or closed cooling systems.<br>