When evaluating knitting corduroy, the most critical factor is the GSM (Grams per Square Meter), which typically ranges from 200 to 350 GSM for apparel. You must also specify the Wale Count (the number of cords per inch); a higher wale count (e.g., 14-21 wale) indicates a finer, softer 'pinwale' corduroy, while a lower count (e.g., 4-8 wale) creates a chunky, bold texture. Additionally, verify the composition, usually a blend of Polyester, Nylon, and Spandex (typically 3-5%) to ensure the necessary four-way stretch and shape recovery.