the OPV is adjustable
but like many manufactures
for small machines
comes completely close from factory

I have an SBux Barista (and am using it at the present time! Need to make a small shelving unit to store my tampers, pitchers, etc due to limited space. Otherwise I'd be using my Gaggia Factory 16!) and I can tell you I tried for YEARS to get it to make decent espresso! Grind, Tamp, nuttin' helped. UNTIL, I got my LeLit PL53 grinder! That, combined with good, fresh beans (and, yeah, you've heard it on this site and others, time and time again. It's TRUE, it's VERY TRUE they contribute an ENORMOUS amount to the coffee making process!) and I'm making some WONDERFUL espresso... Takes (if I did it right) 26-28 seconds for 1.5oz of fluid with AT LEAST an ounce of crema on top and it tastes great! I know the Gaggia will make better (but it's a bit more "touchy" about everything) but the Saeco/SBux Barista WILL make good to excellent espresso as long as you get the grind right and have good, fresh beans! I've killed off all the pressurized bits on the original P/F (removed springs, valves, etc. enlarged opening in bottom of the "spacer", etc). My usual bean is CCC Espresso Aficionado or Toscano

Ntwkgestapo...you related to the "soup nazi"?
Anyway I too purchased a PL53 and its a great grinder!
I also use CCC Espresso Aficionado, and am zeroing in on a perfect setting now.
Thanks for the info. and your time..
Wayneo