Here's a really handy accessory for tube amp builders. Use these and you won't have to drill a bunch of ventilation holes in your chassis. Attractive matte finished aluminum plate measures 2.677" X 2.677". Socket hole 1.417"/36.01mm, tube socket screw mounting centers 1.841"/46.77mm. While we suspect that most of you out there will be using this plate with 'antique' triode four pin Johnson style wafer tube sockets, you should also consider that it fits very nicely all of the 5 pin, 6 pin, 7 pin and 8 pin wafer sockets we offer. Please note that these plates are fabricated on automatic machinery with not a lot of attention lavished on an elegant finish. There are typically some small scratches and marks in the matte finish.The bottom line? These plates look good enough for most D.I.Y. tube amp projects but if you're really fussy you may want to make your own plates.