A CEJN original design for use on traditional tools such as tensioners, wrenches, pullers, power packs and more in harsh and corrosive environments. It features extremely small outside dimensions, and non-drip functionality is a given feature. All exposed components are stainless steel, or even acid proof steel, to provide the longest possible service life and thus save both the environment and money. To further extending service life of the entire hydraulic system both coupling and nipple are provided with plastic dust caps. Aluminum dust caps can be ordered separately.