The AV500 has a unique laser camera projector that enables its small, handheld design and always in focus projection. It also allows for permanent alignment. All other projection vein systems require preventive maintenance to ensure that they stay in alignment. Best of all, the AV500 uses a low power Class 1 laser ensuring eye safety without requiring any special protective gear.The green vein projection shows veins in as both dark lines on a bright background or as light lines on a dark background (inverse mode).