They have multiple law firm clients that need temporary law librarian placement. Depending on the library need it could be entry into a full time placement.
Cons
The hourly rate is based on what firms will pay. Temporary assignments do not have the same hourly rate as a full time employee. So you make less. That's on the client's part and not Pro Libra's. Pro Libra has to put a fee on top of the hourly rate to make their profits.