A lockable cap assembly including a handle having at least one protrusion, and a flip cap defining an internal chamber surrounded by a flip cap edge. The flip cap including at least one locking groove configured to engage the at least one protrusion, and an engagement surface. The lockable cap also including a collar having a release mechanism for engaging with the engagement surface. The flip cap being moveable between an open configuration in which a portion of the flip cap edge is not in contact with a surface of the collar and a closed configuration in which the flip cap edge is in full contact with the collar.