#410R , Size 3 1/2 , Case P , Conn. B- 1/4" MPT , Dial W , Range 600 in 5# increments . It fits in a hole approximately 3 5/8" and as you can see in the photos there are (2) #8 studs on the back . #2471-0 is stamped on the dial

The box is solid but Shelf worn and the brass conn. is faded

Please ask all questions prior to purchase as I do not do returns