The M-37 or 82-BM-37 (батальонный миномёт) is a Soviet 82 millimeter calibre mortar designed by B.I. Szayrin and accepted into service in 1937. The design of the M-37 is based on the earlier French Brandt mle 27/31 mortar with Russian modifications. The M-37M is an improved version with lighter base plate and a device to prevent double loading.