Never seen one of these before and had no idea what to call it other than a spacer insulator, almost like a mid span tramp braket insulator, just 100X smaller. White porcelain and embossed JOHNSON and with the small wire markings on the piece, I guess I would call this a mini transposition insulator for an antenna. The wires are meant to cross each other and one side is lower than the other, so that's my best educated guess. Insulator is perfect and I don't see any chips or cracks. Only flaws are several small missing porcelain corners which are glazed over, so it happened while making the insulator. Very odd for sure and will be an excellent addy to your strain antenna insulator collection. First mail to me.... $12 + actual shipping FCM, so it will be cheap. Outside USA, it will be a bit more. Now $7 + shipping.