152 H 88 is the name of a series of modernized 152 mm towed heavy howitzer

Howitzer

A howitzer is a type of artillery piece characterized by a relatively short barrel and the use of comparatively small propellant charges to propel projectiles at relatively high trajectories, with a steep angle of descent...

s with 32 caliber barrels. The guns of the series share the same barrel as well as other similar qualities, but differ slightly in appearance, since they consist of three different, older (modernized) versions. The modernization was carried out by Vammas Oy from 1988 to mid-1990s. The modernization project consisted of numerous modifications to the guns, some of which had already undergone earlier smaller modifications.