3.5mm Jack Stereo LJE0352-4R

black barrel

includes round knurled nut
 

this is the high quality 3.5mm stereo jack described by NV in his muffwiggler thread: http://www.muffwiggler.com/forum/viewtopic.php?t=71955&highlight=group+jack

it's used by a number of euro format builders, and standard for many synthCube euro kits and assembled modules

check the data sheet-- these jacks have slightly larger bodies and nuts than other 3.5mm jacks and may not be compatible with some panels unless the hole size is modified

a custom nut driver is also available