The 6J6 is an American design. This exhibit, made by Philips, is a copy of that design specification. The inside of the bulb has the blue coating that limits gas emission from the glass.
The grid wires extend outside the working area of the anode.
The Name is Philips but the octagon around the 6J6 looks like an RCA valve.
The thin glass tube envelope is 18 mm in diameter and, excluding the B7G base pins, is 47 mm tall.
References: Data-sheet & 1040. Type 6J6 was first introduced in 1944. See also1944 adverts.