1.double blister card wiht click lock make the paper insert ... not need of heat seal 1. the ways to seal blister packing: folded edge, or by High Frequency, Hot-sealing, ... snap close,by nail.2. blister packing is available in clear,silk screen printing ,offset printing,gold ... foil,silver foil,laser foil 3. blister packing is always available in PET,PVC ...