2nd Generation is primarily used by law enforcement or for professional applications. This is because the cost of a 2nd Gen. unit is approximately $500.00 to $1000.00 more then a 1st Gen. The main difference between a 1st and a 2nd Generation unit is the addition of a micro-channel plate, commonly referred to as a MCP. The MCP works as an electron amplifier and is placed directly behind the photocathode. The MCP consists of millions of short parallel glass tubes. When the electrons pass through these short tubes, thousands more electrons are released. This extra process allows 2nd Generation units to amplify the light many more times then 1st Generation giving you a brighter and sharper image.