When sourcing this specific blend, commonly known as stretch twill or poplin, you must verify the Fabric Weight (GSM); typically, 120-150 GSM is used for shirts, while 200-300 GSM is standard for trousers. Ensure the Yarn Count (e.g., 32s, 40s) matches your durability needs. Most importantly, test the Elasticity Recovery Rate—high-quality fabric should return to its original shape without 'bagging' after stretching. Confirm the Shrinkage Rate is controlled within ±3% through pre-shrinking processes like Sanforizing.