GLS Audio 1/4" Locking Panel Jack - "D" Size
Can be used for both TS (mono/unbalanced) and TRS (stereo/balanced) applications.
Pinout (looking at back of jack):
Left Pin - Negative Ground Sleeve (This pin is the thick pin for S in both TS and TRS)
Center Bottom Pin - Positive Tip (This pin is used for the T in both TS and TRS)
Right Pin - Positive Ring (This pin is used for the R in TRS. It is not used for TS)