81mm wz.31 mortar was a version of a classic*
Stokes-Brandt Mle 1927. They were bought in France*
in 1931, and then produced in Poland since 1934.*
*
Earlier there were used other 81 mm mortars:*
Stokes-Brandt wz.18 and Polish wz.28 and wz.30 Avia.*
*

_____________[description by PIBWL]*