Holophane orig antique prismatic glass shade, vintage industrial light

Old glass shade for industrial lighting (probably for a ceiling pendant light, though we've seen shades like these on swing arm desk or work table lights, too).

This is marked Holophane (B2) and measures 6 3/4" in diameter, 2 1/4" at the fitter, 5" deep. It's in excellent condition, no chips or damage.