The M-55S is a domestic upgrade for the T-55A's that Slovenia had several dozen off in storage after the Yugoslav Wars.

The tanks were upgraded with a new FCS, a 105mm gun as well as an improved engine and the notable "Blazer" ERA, which was mounted on the turret cheeks and hull front.

Most of these tanks were later on sent to Ukraine as a donation in 2023-2024 and have been fighting there since then, likely the same vehicles as pictured here from the late 90s