Jennings vacuum relay. DPDT 26vdc, 275 ohm coil. Fits 3/4" hole, extends 1-1/2" above the mounting ringbase, extends 1/4" below mounting ringbase. The mounting ringbase is 1-1/2 inches in diameter. Contacts are rated at 20A 12kv/6kv. $55.00 shipped. If interested contact me off list for more details and pictures. J W7KSG