Heavy duty all plastic cups with molded hooks to attach to the outside of your cage. Lift up clear plastic flip up lid to fill without opening the cage door with no risk of escaping birds. The clear plastic lid allows you to see the contents. Small vents in the base to allow air flow to prevent dampness. May be used for feed, grit or anything you wish you birds to have access to. The one hole is 3.5 x 4.33 x 5.5. The two hole is 6.75 x 4.5 x 5.5 and the three hole is 10.25 x 4.33 x 5.5.