Vivitar Replacement Vari Sensor Module for 285HV Flash

This Replacement Vari Sensor Module for 285HV Flash from Vivitar measures the light reflected from the subject of a photograph and automatically adjusts the light output of the flash if there's a change (if you move closer or farther from the subject, for instance), so you don't need to change the f-stop on your camera.

The sensor plugs into the front of the flash and can be set for manual or automatic operation at four different f-stops, using the color-coded mode selector dial. Yellow represents the widest lens opening and the greatest automatic operating range, and purple uses the smallest lens aperture for maximum depth of field.