Grover HS100N Slimline Guitar Machines. Fit classical guitars with slotted headstocks. They may fit other guitars but they definitely fit certain Martin nylon string guitars from the '50s, '60s and '70s. These are NEW OLD STOCK (Made in USA) in original box. I know they are from the '70s because I ordered some for a customer's Martin repair and I ordered an extra set. They've been safely aging in the repair department of our stores for years. OUR PRICE: $ 99.99 with FREE SHIPPING to U.S. Addresses.