Cr4+:YAG crystals have several advantages when compared to traditional Passive Q-switching choices such as organic dyes and colour centres materials. Crystal Passive Q-switch is preferred for simplicity of manufacturing and operation, low cost, and reduced system size and weight. Cr4+:YAG is chemically stable, UV resistant and it is durable. Cr4+:YAG will operate over a wide range of temperatures and conditions. The good thermal conductivity of Cr4+:YAG is well suited for high average power applications.