Adhesive strength refers to how sticky your graphics are. For 90% of RC graphic applications, standard adhesive strength works just fine. Hyper Stick adhesive is recommended for tougher surfaces like HDPE plastics (such as unbreakable bodies), foam, powder-coated metals, and most plastics outside of standard Lexan RC bodies. The same idea applies to flexibility. Standard materials work for most applications, but if you're looking for something extra soft and pliable—especially for wrapping around curves without wrinkling—HyperFlex is the better choice. Please note: at this time, HyperFlex is not available combined with Hyper Stick. If you have any questions, feel free to email me!