These extensions are truly universal, with a JR/Universal connector on the receiver end and a Futaba J connector on the servo end. This means that you can plug any servo into the extension, and plug the extension into any receiver. The extensions are ideal when you need to put a servo (or speed control) farther away from the receiver than the stock wire on the servo will allow.
Used with permission, copyright 2016 Common Sense RC. Copyright 2016 Brey Corp. t/a Hobby Works.