*You can use the new SD-2025 receiver collar as a replacement for the PA-015 receiver as long as you do not use PA-015 and SD-2025 on same transmitter as sometimes they react at very different proximities to flag area. When you only use the SD-2025 model you adjust the field width so dog gets beep at six feet from wire and you are good to go! You can use more than one SD-2025 on a system. Find the SD-2025 under Extra Collars heading.
The PA-015's were the rechargeable receivers with black plastic case and the recharge socket at the center of one end of the receiver back. Recharge socket contains red indicator light.