1/4" phone jack (mono) for thick panels. Long threaded bushing with washer and nut.
I bought 14 of these and have had problems with most of them. They DO NOT make reliable connections when inserting connectors. Not worth RMA, but will NOT buy any more of these.
This is a nice jack. Too Bad the description doesn't say it is MONO
I have dealt with MCM Electronics a number of times and have been more than satisfied.