From Batchwork Software:
Batch PPTX AND PPSX Converter is a PowerPoint PPTX to PPSX, PPSX to PPTX Batch Converter that can convert PPTX to PPSX (ppt to pps) and PPSX to PPTX (pps to ppt) easily. Batch PPTX to PPSX Converter supports powerful search for batch files. Batch PPTX AND PPSX Converter supports project and command line. Batch PPTX AND PPSX Converter has a friendly GUI so it is used very easily. Batch PPTX and PPSX Converter works fine without PowerPoint installed. Batch PPTX AND PPSX Converter supports a efficient Multi-Thread conversion engine. So you could control the conversion action very easily. You can stop or pause and continue it in any time.
Features of Batch PPTX to PPSX Converter includes convert PowerPoint PPTX (ppt) to PPSX Show (pps) and PPSX to PPTX easily, Batch convert PPSX to PPTX and PPTX to PPSX with GUI that supports powerful search function, supports convert a ppt or pptx or pps or ppsx file, supports convert ppt or pptx or pps or ppsx files in a folder, and drag and context menu with Microsoft Explorer supported.