The Teslong NTG450 36-inch Flexible Rifle Borescope comes with a 4.5inch IPS HD monitor. It is perfect for those who do not carry a smartphone or do not wish to connect a camera device to their phone. This borescope is very useful to monitor the build-up of carbon fouling and copper and to visualize which cleaning products work well for your application. This borescope is also invaluable for inspecting the barrel of any used firearms you are considering purchasing. Wear, rust, pitting, fire-cracking, throat erosion and other defects can easily be seen before you make a purchasing decision. This stand-alone unit is easy to transport to a gun show or shop. The Lens is 0.2” and will fit 204Ruger caliber sizes and upwards. It can can be used on its own as well without the screen on any Windows or Mac computers. The Teslong 5-Mirror set is also included when you purchase the NTG450.