you very intelligent , really i watch that pic for many min but this thing doesnt come in my mind , inspite of the fact that once i have use this tool , but in big size ,,,,,,,,,,,,,,you know vespa ? ,,,,,,,,,,,(i am a big fan of it and i have restored my dad's vespa) there is no head gas kit on it , its desighn in a way that you wont need any gaskit ,,,,,,,,,,,,years before my vespa leaks some pressure from head and cylinder ,,,,,,,,,,so i plan to make a gas kit for it ,,,,,,,,,,,,,,and in that i use this tool which have a diameter of about 57mm