Iran presents Hoveyzeh 155mm self-propelled howitzer based on the M-109A1B american howitzer 2104145.

The Iranian army has ordered 50 M109 in 1970. These were later upgraded to M109A1 standards, and a further 390 M109A1B were obtained in the late 1970s prior to the fall of the Shah and the advent of the Islamic Republic.

The M109A1 is basically the M109 fitted with a new and much longer barrel, designated the M185, an improved elevation and traverse system and a strengthened suspension system.

The M109A1 fires an HE projectile to a range of 18,100 m compared with the 14,600 m of the M109, while a rocket-assisted projectile extends the range to 24,000 m.

The M109A1 was type-classified as Standard A by U.S. army in October 1970 with first conversion kits made available early in 1972 and the first vehicles, which were converted from standard M109s, becoming operational in 1973. The M109A1 weighs 24,070 kg fully loaded and is 9.042 m long including the barrel.

The hull is made of all-welded aluminium armour which provides protection against small arms firing and shell splinters.