La Pavoni Europiccola & Professionale Safety Valve Body Millennium, Hole diameter is 6,5mm This is just the safety valve body and does not include the internal components. This Safety Valve Body is found on most Millennium Europiccola and Professionale models (equipped with Pressurestat and a 2-prong Heating Element), and it goes with the newer style safety valve MP-39 SP/SE. For Pre-Millennium Professional machines: if you already have the MP-39 SP/SE on your unit, then this is the correct Safety Valve Body. If you instead have a spring + ss ball / Teflon mushroom combination on your Professional, you can upgrade to this valve body as long as you also upgrade to the MP-39 SP/SE. For Pre-Millennium Non-Professional (8-cup, no factory-installed gauge) versions, which use the P-39 SP or SE spring + ss ball / Teflon mushroom, we suggest replacing the valve body with P-37 Note that we offer two tools to assist with removing and reinstalling this assembly, the Steam Valve Removal Tool to reach the nut inside the boiler and the Pavoni Skinny Wrench to hold the base of the MP- or P-37 in place while loosening/tightening. PLEASE NOTE: As with many manufacturers who are making an effort to cut their production costs, La Pavoni has stopped finishing the inside piece and the lower part of the outside piece of this assembly. All, or at least most, of the unfinished portion is hidden by the drain tube cup. They are still properly finishing the top end.