Termination & assembly
The SP-35401 is a male 3.50 mm phone plug with a 4-conductor TRRS signal layout, terminated by soldering the wires to the contact posts inside the handle. The free-hanging in-line design uses an M8x1 threaded barrel and includes a strain relief and a two-piece handle (connector plus handle) to secure the cable jacket after soldering.
Mating length & contact finish
Mating depth into the jack is 0.551" (14.00 mm); the brass contacts carry a nickel plating, and the housing is PVC with a brass body. No internal switch is present — the plug is a straight-through TRRS connection.