The S400 is the strongest solar energiser in the market. With the 40 Watt solar panel, the S400 can power fencing of up to 30km. Even after one week without direct sunlight, the energiser still has enough power to put enough voltage on your fencing. The S400 is extremely suitable for temporary fencing that covers a reasonably large area. It means you have enough voltage on your fencing, without needing a socket nearby!