3M Scotchcal Label 3690+ utilizes a durable PVC facestock and a special modified acrylic adhesive. The adhesive is designed to adhere well to difficult surfaces such as rough and porous substrates, and low surface energy materials such as polyethylene and polypropylene. It is suitable for outdoor applications, which require a high degree of durability. Their thin caliper and flexibility allow for conformance to small diameter and complex curved surfaces.