Strap size of 42mm PO

[jamhoe2]

Hi guys,
looking for a 42mm PO strap for my friend . the strap must fit the orginal deployment buckle, am i correct to say its 22/20 ?

[anakin]

my 45.5mm one is 22mm. may be the 42mm one is 20mm? purely speculating so get a confirm answer before buying pls .