Child-resistant and airtight container

A method of effecting a container comprising:

• providing a container comprising a base and a cap;
• wherein the base comprises a closed bottom end, a neck having an open top end, and a cap engagement element,
• wherein the closed bottom end has a substantially planar bottom surface and includes a plurality of protrusions that extend radially inwardly from the base at the closed bottom end without extending beyond the planar bottom surface, the protrusions configured to engage with and secure another container cap for stacking the container on top of the another container cap,
• wherein the closed bottom end further comprises a recessed floor that is recessed inwardly relative to the planar bottom surface for mating with the another container cap,
• wherein the cap engagement element is disposed on the outer surface of the neck, and
• wherein the cap comprises a base engagement element configured to couple with the cap engagement element;
• and
• moving the cap over the open end of the base, wherein the cap engagement element couples to the base engagement element.

A container comprising:

• a) a base comprising a closed bottom end, a neck having an open top end, and a cap engagement element positioned on a first side of the neck, wherein the closed bottom end has a substantially planar bottom surface and includes a plurality of protrusions that extend radially inwardly from the base at the closed bottom end without extending beyond the planar bottom surface, the protrusions configured to engage with and secure another container cap for stacking the container on top of the another container cap, and the closed bottom end further comprises a recessed floor that is recessed inwardly relative to the planar bottom surface for mating with the another container cap;
• b) a cap comprising a base engagement element on an inner surface of the cap, wherein the base engagement element is configured to engage with the cap engagement element;
• and
• c) an annular sealing ring on an inner surface of the cap.