Callaham Stratocaster Tremolo Bridge, For Standard Stratocaster (Mexico), w/Pop-In 64-Length Arm Made in the USA using premium vintage-correct materials. Complete tremolo unit, as pictured. 2-1/16 screw and string spacing. For Standard Stratocaster (Mexico). Features Callahams Enhanced Vintage block and Virtual Pop-In arm. Arm fits snugly, with no play. Hardened steel saddles (over 100 Rockwell B) - nickel plated - for great tone, great looks! 1018 cold-rolled steel block like the vintage originals for better sustain & harmonic content.