Cisdem PDF Compressor is the smartest PDF compressor to reduce PDF file size on Mac. By drag and drop, you can compress PDF files in batches. There are 4 preset filters: Small File Size, Medium File Size, Large File Size and Custom, allowing you to reduce PDF file size up to 90% and keep the best quality. Key Features of Cisdem PDF Compressor 1. Compress PDF files in batch. 2. 4 preset modes: Small File Size, Medium File Size, Large File Size and Custom to meet all your needs on PDF compression. 3. Keep the highest quality: only remove the useless elements to reduce the large PDFs without compromising quality. 4. Support all versions of PDF documents.