Hy mamboitaliano, "weatherhead" is the name of the fitting manufacturer, I gave you the name so that when you went to pickup the parts you could tell the kid with the nose ring or bolt through his eyebrow that you want two "weatherhead" part number 6100X2 nuts and one 6200x2 male connector. By the way the X in the part number is actually a by sign, so when you ask ask for two 6100 by 2 fittings and one 6200 by 2 fitting, hope that helps.
