Based on this product's specifications, here are some alternatives and similar models
Plastic Document Sleeve Bantex A4, 100 µm polypropylene, pack of 25, clear
Summary description:
A4 plastic document sleeve by Bantex made from 100 µm polypropylene. This clear, uncoloured sleeve protects single A4 sheets from dirt, moisture and creasing. Supplied in a pack of 25, it is suitable for office filing, presentations, archiving and everyday document protection where a thin, durable transparent cover is required.