Original, manufactured in the 1970s, electro-harmonix Doctor Q "Envelope Follower" An envelope filter with an intense effect. It responds well to picking nuances, and with an unusually wide variable range, it allows for very simple yet profound sound creation, from chord cutting to leads and even experimental uses. There are scratches and other signs of wear and tear appropriate for its age, but there are no issues with its use. The screws holding the case are stripped, but they will not come off during normal use. As this product is nearly 50 years old since its release, there is some very slight crackling, and there is also a sense of use, so please refrain from bidding if you are looking for a new item. In addition, due to the rarity of this vintage item, returns after purchase are not accepted to prevent parts replacement.