Review on 10 Sets of Retractable Sheath 4mm Banana Plug Connectors: Stackable Wire Solder Multimeter Test Leads with Banana Plug Adapters and Jack Sockets by Brian Cueto

The spring is too strong and the plug is not long enough. In particular, if you pull it from the socket just a little bit, it pops out completely. The Pomona connectors need to be pulled out much further before they fall out. The jack portion does not accept shielded banana plugs. This can be seen in the photo if you look closely, but that's an odd oversight as they're kind of shielded. I call it "type of shield" because the shield is a custom diameter, which means it will retract even if you use it in a shielded outlet.