Polyester and Nylon Slings look the same but there are a few differences. Polyester slings have low stretch which is ideal for low headroom applications. The coarse edges protect against abrasions. The polyester absorbs less water making it slightly more suitable for outdoor use. In comparison, Nylon slings stretch 8-10% at the working load limit and hence they are more shock absorbent. The soft edges are more prone to abrasions but protect delicate loads better. The nylon fabric absorbs more water making it less suitable for outdoor use.