CLIFF S1C Series Stacking Jack Connectors 6.35mm Twin mono stacking jack.

Cliff Stack Jack 0.25" (6.3mm) switched jack sockets with patented NI-AG alloy self-cleaning contacts.
Super-compact body size enables the highest board packing density available.
Snap in PCB mounting permits wave soldering and ease of assembly.
Available in 2 versions single and double with spacer styles have fully threaded nose and nylon mounting nut.
Double without spacer styles do not permit use of mounting nut but enable a compact stacking profile
with spacing of only 12.7mm.

RoHS compliant