When selecting a custom stamp pad, you must evaluate the ink base (water-based, oil-based, or solvent-based) to ensure compatibility with the intended surface. For office paper, water-based inks are standard, while solvent-based inks are required for non-porous surfaces like plastic or metal. Additionally, verify the pad material, such as high-density felt or micro-porous foam, which affects ink retention and impression clarity. Ensure the housing is made of durable ABS plastic or tinplate to prevent leakage and drying during long-term storage.