This is an aftermarket replacement for the ESB 20-minute mechanical timer, commonly used on Elite models, but found on many others. The hole pattern is rotated 90 degrees, so you'll either have to drill two small holes in your timer bracket to mount it properly on older models, or use our replacement knob that is also rotated 90 degrees to maintain compatibility. Replaces original style timers that resemble this one shown here:

This is what the back side of this replacement timer looks like: