A security bag, also known as a tamper-evident bag, is a type of bag that is designed to protect the contents of the bag from tampering or unauthorized access. Security bags are typically made of a strong, durable plastic material and have a closure system that is difficult to open without leaving visible evidence of tampering. Security bags are typically marked with a warning or notice that indicates that the contents of the bag are protected and that any attempt to open the bag without authorization will be detected. This helps to discourage tampering and to ensure the security of the contents.