It is used to measure the growth of the low elastic knitted fabric, the elongation of the fabric, and the recovery performance of the fabric (the fixed load performance and the fixed elongation performance). That is to say, under certain conditions, the growth of the specimen after a certain load is measured, and the tension is applied to the sample within a certain time to remove the difference between the length and the original length of the specimen after tension. It is mainly suitable for low elastic knitted fabrics, such as swimsuit, sportswear, loose fitting or other tight fitting.