Abstract: Systems and methods of permanently marking a material containing an opacification material may include marking the material with a laser system. The laser system may be an ultraviolet system, and the laser may be a solid state diode pumped and pulsed 4 watt to 55 watt unit with a minimum scan speed of 3 meters/second and a minimum frequency of 30 KHz.

Abstract: Valves useful for pressure relief/ventilation/vacuum or pressure retention, particularly in packaging containers, are disclosed. The present valves include a first member which is substantially rigid, includes an outer sealing region and a raised section having at least one hole therethrough; and a second member which is substantially elastic, is in close proximity to, preferably in contact with, the raised section of the first member and is sealingly secured the first member at the outer sealing region. The second member includes at least one through hole located outwardly or outboard of the raised section of the first section and inwardly of the outer sealing region of the first member. The elastic member may be moved away from the raised section to equalize gas pressures between a container and the environment outside the container or is urged into more intimate contact with the raised section to prevent gas flow into or out of the container.