Double blister packaging refers to a packaging form that uses two blister packages to encapsulate the paper card and the product. Its characteristic is that a high frequency machine is needed to seal the double-bubble shell, the efficiency is low, the packaging cost is higher, but the edges are neat, and the product appearance is high-grade. The issues that should be noted are: 1. The bubble shell can only use PVC and PETG film, otherwise it cannot be heat-sealed or the heat-sealing effect is not good; 2. The quality of the high frequency mold determines the quality of the double bubble shell edge.