Filled with clean water to flush away dirty soap residue.
The (acronym for Zakład Sprzętu Dołowego - 74 , meaning "Downhole Equipment Plant - 74") is a Polish-designed and manufactured specialized armored vehicle. Contrary to what the industrial designation suggests, it is not associated with drilling equipment. The "74" refers to the development year (1974) and the plant code. ZSD-74 L