You're gonna hafta be more specific about which you want, as the heater design, including the knobs, changed mid-way through the 4E series. The early ones were the same as the the 2R-3E series, but the three knobs each attached differently.
One of the knobs comes attached to the control wire, and is not removable from it. The later design used the same Lark-era knob on all three controls.
Posted on Jul 31, 2012, 3:11 PM from IP address 22.214.171.124