Power adapter sized to operate many pet containment system transmitters. A used power adapter means that even though it is tested and working it my not look new. Dust, scratches in the surface and possibly some paint may be on the exterior of a power adapter, but will not affect its correct operation. Limited 12vdc output models available - inquire by email. All power adapters can be used on most basic dog fences; Either 750ma or 1000ma for IFCO and other professional grade brands. Look at your owners guide or label on transmitter for specifications. No refunds on Power adapters.