Generally, tamper evident bag consist of two main parts, a PE bag and a tamper evident void seal. Besides these two parts, also there can be tear-off receipt, inside bubbles, 

                                                 embedded small bag, build-out small bag, etc. So tamper evident bag is a comprehensive product, when we choose it, we should consider various parts of it.

                                                 1, A HDPE bag is recommended. HDPE can make bags be dense.

                                                 2, A suitable thickness of bags. If the contect in there is light, then we make the bag thinner, if the contect is heavy, we make it thicker.

                                                 3, Choose a flat and easy-printing bag. Or when you print barcode or serial number on it, it will be blurry.

                                                 4, A strong edge banding. Or the content in there will slip out unconsciously.

                                                 5, A qualified tamper evident void seal is important which is the soul. When tampered movement happens, the 'VOID' words will come out.

                                                 6, Also besides 'VOID' function, maybe there are other functions needed, such as 'Freezing Resistance', 'Prevent Hot Wind Tampering', 'Prevent Solvent Tampering'. So if a multi-functional tamper                                                           evident bag is needed, then we should have a more serious qualified tamper evident seal.

                                                 7, If some assistant parts needed, such as tear-off receipt, inside bubbles, embedded bag, build-out bag, then we should have an accurate design for the whole bag.

                                                 These are the points we think should pay attention to when we buy a tamper evident bag. Tamper evident bag is not a very complex product, but if you want a satisfied, stable, qualified product, also                                                       it will consume your energy. May this will help.