Airless metered fluid dispenser assembly

A metered dispensing assembly comprising:

• a dispensing nozzle;
• an end cap housing;
• and
• a lock-out mechanism;
• wherein said end cap housing is configured to engage a reservoir;
• wherein said lock-out mechanism prevents more than a single dose of a predetermined amount of a material housed within said reservoir to dispense through said dispensing nozzle without first being manually returned to a pre-actuated position by a user;
• wherein said lock-out mechanism comprises a locking sleeve and biasing element;
• and wherein said locking sleeve comprises a locking structure configured to prevent movement of said dispensing nozzle after said dispensing nozzle undergoes an actuation;
• wherein said locking structure comprises a plurality of notches;
• and,
• wherein said end cap housing comprises one or more locking teeth located radially outward from the locking sleeve and configured to engage said locking structure such that when said dispensing nozzle undergoes said actuation said locking sleeve actuates with said dispensing nozzle, said one or more locking teeth engage said locking structure to substantially prevent said dispensing nozzle from returning to said pre-actuated position, when said dispensing nozzle is rotated to align said locking teeth and a plurality of notches, based on a distal force applied by said biasing element.