The most commonly used slip additives are erucamide (C 22-) and oleamide (C 18-). Oleamjde migrates quicker than erucamide and is often called “fast blooming”. However, after a certain time, the slower erucamide will provide films with a lower COF than oleamide. Erucamide, with its lower vapor pressure and volatility, is used in higher temperature processing applications and it also stays at the surface longer, not venting off as smoke. Oleamide is used where a low COF is needed in a short period of time, while the slower migration of erucamide can be advantageous in roll stock applications and online corona treatment. Another fatty acid amide is Streamside. This is often used together with erucamide or oleamide to provide an anti-blocking effect when film transparency is very important. The concentration of slip present affects performance. Initially, the COF is sensitive to small variations in concentration until a critical level of slip is reached, after which further slip has little effect on the COF. The amount of slip required depends upon film thickness, the slip additive being used, and the presence of other additives such as anti-blocks.