Actually none. The wire from the LyxPro cable is rather thick, strong enough to withstand certain pull force. At the headphone ends, the heat shrink is rather tight fit with the cable hole of the 2.5mm connector. At the 3.5mm end, inside the jack there is the common clamp for the wire. So far so good, and I always hold the connector when pulling out, not the cable, so no problem so far.