Based on this product's specifications, here are some alternatives and similar models
Paper Back Pocket MAILmedia C5, 90 g/m² paper, 22.4 g adhesive
Summary description:
MAILmedia C5 paper back pocket designed for document storage and mailing. Made from 90 g/m² paper with 22.4 g adhesive for secure sealing. Suited for attaching to envelopes, mailers or folders to hold invoices, brochures or documents. Provides a lightweight, economical way to protect and organize paperwork during transport and delivery.