This little milky glass shade reminds us of a diver’s helmet seen in old television programs, hence the name. She is 5 inches wide, 5.5 inches deep and 4 inches tall. The opening is 3.25 inches from outside lip to outside lip. She’s in good condition, with no cracks or breaks. A wonderful replacement piece if clumsy fingers have left you with a wall light and no suitable shade for it.