E3631A, E3632A, E3633A, E3634A. 6611C, 6612C, 6613C, 6614C, 66309B, 66309D, 66311A, 66311B, 66319B, 66319D, 66321B, 66321D. Also fits to HP / Agilent 33120A Function / Arbitrary Waveform Generator. This knob for D-shaft encoder.
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