Welch Allyn Ophthalmoscope Bulb Replacement Bulb for Welch Allyn Ophthalmoscope Bulb #04900 Volts: 3.5 Watts: N/A Type: Halogen Fits Models: Welch Allyn • 11620 • 11630 • 11720 • 11730 • Each line represents 0.125 of an inch. • This chart is to be used as a guide only. • Sizing chart enlarged to show detail.