Abstract: A multi-speed jack, having a pump assembly including a pump block having a first cylinder and a second cylinder defined therein, a piston assembly movable within the pump block, the piston assembly having a first portion configured to sealably engage with the first cylinder and a second portion configured to sealably engage with the second cylinder, a reservoir for storing hydraulic fluid and coupled to the pump block so that when the piston assembly is moved in a first direction, hydraulic fluid in the reservoir is supplied to the first cylinder and the second cylinder, a lifting assembly having a ram chamber and a ram rod, the ram chamber coupled to the pump assembly and configured to receive fluid from the first cylinder and the second cylinder when the piston assembly is moved in a second direction so as to raise the ram rod and a bypass check valve provided in the first cylinder.

Abstract: An optical system is provided that has an enclosure which is substantially filled with a fluid. The enclosure also has an aperture for receiving an electromagnetic wave that is altered by an optical component contained in the enclosure. The enclosure also has an aperture mask and blocker that are at least partially immersed in the fluid.