Nickel plated button fits USA Vintage Series Jazzmaster and Jaguar exactly and are the best available replacement parts for '60s original Jazzmasters and Jaguars. The Trem Lock button sits on top of the tremolo plate and slides in a slot to lock the tremolo action. Great for restoring older Jazzmasters, Jaguars and for for replacement use in USA Vintage Series instruments. Brand New. Genuine Fender 0054474000. UPC 717669154578.