The supplement is unopened. When purchased online, a sticker was directly affixed to the cover, and removing it caused a nearly imperceptible scratch. Please understand that this is a vintage item stored by a private individual. Experience the World's First Electronic Instrument Played Without Touching: Invented in 1920 by Dr. Lev Termen, the Theremin is the world's oldest electronic instrument, a unique instrument played by moving your hands closer to or further away from the antenna. ★Adult Science Magazine Masterpiece Supplement Revival Series, 6th Edition★ [Kit Features] ▼ This is a simplified Theremin, using only the pitch-changing antenna out of the usual two antennas for pitch and volume control. ▼ Built-in speaker allows you to produce sound immediately after completion. It also has an output terminal, so you can connect it to an amplifier. ▼ Easy to assemble with just one screwdriver. Assembly time is 30 minutes. ▼ The magazine is filled with articles on how to play the Theremin, including a Theremin lesson. ※ Requires 4 AA alkaline batteries (sold separately). ※ This product is a revised version with some specification changes from the supplement of the "Adult Science Magazine Theremin mini" published in 2007. Changes: The antenna has been changed to a durable aluminum pipe. An earth terminal to stabilize the pitch and a 3.5mm stereo mini-plug compatible external output terminal have been added to the back of the main unit.