Star PDF Watermark 1.6

Star PDF Watermark is a batch PDF watermarking tool for Mac, you can fast add text or image watermark to Acrobat PDF file, such as add signatures, company name or company logo to protect you PDF file copyright.

With PDF watermarking software free version, you could add TEXT water mark for your PDF files, With PDF watermark software purchased version, you can add not only TEXT watermark, but also IMAGE watermark to your PDF document.
There are 3 editions of Star PDF Watermark: the free version, plus Professional ($29.50) and Ultimate ($36.99).Their demo files can be downloaded from 'Related Links' (see below). The differences between the versions are explained here.