I have just started using my solder connectors and I can tell you that they are of very poor quality. I've ordered similar soldered connectors from another vendor at Revain in the past and the plastic was of a much better quality as it didn't melt when attempting to heat the connector. The quality of the solder inside isn't very good either, it's not as viscous and doesn't stick together as well as the ones I've used before. I will never buy from this seller again.