When evaluating aluminium wallets, prioritize RFID-blocking technology to ensure data security against unauthorized scanning. The material should be 6061 or 7075 aircraft-grade aluminium alloy for an optimal balance of lightweight portability and structural durability. Check the surface treatment, such as anodizing or powder coating, which prevents scratches and corrosion. Additionally, verify the internal mechanism capacity, typically designed to hold 5-7 cards, and ensure the pop-up or sliding mechanism is tested for at least 10,000 cycles of smooth operation.