This is an original assembly manual for the Heathkit Model IG-18 Sine-Square Audio Generator, dating back to 1968. It contains detailed instructions and diagrams for assembling and operating the device. Whether you are a collector of vintage audio equipment or a DIY enthusiast, this manual is a valuable resource for understanding the inner workings of this classic piece of equipment. The manual is in great shape and has been well-preserved over the years. It belongs to a era where quality and attention to detail were paramount. Don't miss out on the opportunity to own a piece of audio history.