Apparatus has a body with a conduit defined therein. Body is mounted between, and connected to, a charging system containing pressurized fluid and a pressurized system. One apparatus has a retractable discharge tube inserted into a first end of the body. Once the body is connected to both the charging system and the pressurized system, a force is applied on the charging system toward the pressurized system. The force causes the charging system and the pressurized system to mate with the body urging the discharge tube to retract to release fluid into the conduit, and actuates the fitting to permit the fluid in the conduit to enter the pressurized system. Another apparatus has a manually deformable charging system and an adapter with a check valve to permit manual urging of fluid in the charging system through deformation of the charging system.