This is a tremolo tailpiece that commonly turns up on the Fender® Jaguar and Jazzmaster® guitars – it’s a strange beast frankly – differing from most other trems fitted to Fender® guitars by being built entirely into the tail piece rather then the bridge (ala Strat®)

It is, honestly, a bit of a pain in the modern age – but it was pretty revolutionary when it was designed (even if it wasn’t all that loved, and never really worked all that well (atleast in my opinion)

This model is fitted with a “locking button”, and for that to be used, and actually function, the guitar will need to be set up ABSOLUTELY INCH PERFECT!

I won’t lay any claim to knowing the delicate ins and outs of the Offset series – because, frankly, I don’t – but theres a few resources out there that explain how the trem systems work.

https://mmguitarbar.wordpress.com/2013/05/10/demystifying-the-fender-jazzmaster-and-jaguar-part-3-free-your-mind-and-your-tailpiece-will-follow/

Credit to Mike and Mikes Guitar bar frankly, because that’s about as well as I’ve seen it laid out.

This is another good little guide to whats going on by Tom Arnold
https://offset.guitars/the-goodies/setting-up-the-...

Essentially, both the Jazzmaster® and Jaguar® REALLY want heavy strings on them – 11s seem the order of the day – you need enough tension in the strings to put the tremolo into equilibrium – and when your setting up the trem, you slide the locking button “back” (towards the tail piece, you cant “whammy up” basically) – you tune up the guitar, and then slide the button forward.

This means you can now “whammy down” and “whammy up” – and all is well and good. If you ever want to “lock” the bridge, then you slide the button back – you can still “whammy down”, but not up – which is frankly, a bit of a nothing feature when everythings working as it should, but its very handy when a string breaks – the lock button is (assuming all the stars align!) set at the point of perfect equilibrium – and removes the need to have the trem in balance, so when a string goes, and the balance is lost – quick and easy to get the guitar locked off and back in tune.

It is, honestly? A weird idea – but it does work… but it really does need big strings! (not enough strength in the string, and the tremolo wont slide forward as it should, and the lock button will miss the locking plate)

So yeah – its historic, its something the Offsets have always had, its handy, but it’s a bit of a faff, and requires a bit of setting up to get it working perfectly.

Fender®, Jazzmaster® Jaguar® are registered trademarks of Fender Musical Instruments Corporation and Axesrus ® has no affiliation with FMIC