Oshlun 2nd generation laser guides are the easiest and best way to turn your saw into a precision cutting machine. Installation is fast and easy, simply replace the outer blade flange with the laser guide unit. There are no confusing parts or adjustments. The new design provides a brighter, more accurate line on the left of the saw blade kerf and improves safety by showing you where the blade will cut well before reaching the material. The centrifugal switch activates the laser automatically.