The 5109E is a finger-grip knob with an integrated pointer, designed for use with rheostats and tap switches. This knob has a diameter of 1 5/8 inches and is made to fit a 1/4 inch shaft, to which it is fastened by a slotted set screw. It is specifically compatible with Ohmite rheostat and tap switch models H, J, G, K, and L. For applications requiring a visual scale, it can be used in conjunction with the 5002-* series dial. This knob provides a durable and precise manual control interface for adjusting electronic components.