Supervisors.

A supervisor is first and foremost an overseer whose main responsibility is to ensure that a group of subordinates get out the assigned amount of production, when they are supposed to do it and within acceptable levels of quality, costs and safety.
A Supervisor is responsible for the productivity and actions of a small group of employees. The Supervisor has several managers like roles, responsibilities, and powers. Two of the key differences between a Supervisor and a Manager are (1) the Supervisor does not typically have "hire and fire" authority, and (2) the Supervisor does not have budget authority.
Lacking "hire and fire" authority means that a Supervisor may not recruit the employees working in the Supervisor's group nor does the Supervisor have the authority to terminate an employee. The Supervisor may participate in the hiring process as part of interviewing and assessing candidates but the actual hiring authority rests in the hands of a Human Resource Manager. The Supervisor may recommend to management that a particular employee be terminated and the Supervisor may be the one who documents the behaviors leading to the recommendation but the actual firing authority rests in the hands of a Manager.
Lacking budget authority means that a Supervisor is provided a budget developed by management within which constraints the Supervisor is expected to provide a productive environment for the employees of the Supervisor's work group. A Supervisor will usually have the authority to make purchases within specified limits. A Supervisor is also given the power to approve work hours and other payroll issues. Normally, budget affecting requests such as travel will require not only the Supervisor's approval but the approval of one or more layers of management.