Shallow Saucer 19" White Acrylic (3-5/16" Deep, 19-3/16, 16-3/8" Fitter) (item # 4114-SI-S19W) This diffuser family utilizes a shallow saucer design to give maximum light output in a classic shape. Measurements: 19-3/16" across, 3-5/16" high, 16-3/8" inside ring.