I am not sure if these are the original authentic XT60 connector. I think the originals say Amman on them or something, but these do work really good. They look to be nylon and can take the heat of soldering without deforming. Usually I will use a mating connector while soldering to be sure there is no movement and every thing lines up. if you have melted one of these or the bullet moves while making a joint you are doing something wrong. Price is right, and XT60s are the most user friendly. I measured about 3.0 ohms of resistance with male female connected. not bad. convenience is worth it.