When selecting a Jiu Jitsu Gi, the fabric weave is the most critical factor. Common options include Single Weave (lightweight), Double Weave (heavy/durable), and Pearl Weave (the industry standard for competition). You must ensure the GSM (Grams per Square Meter) aligns with your needs; typically 350-450 GSM for lightweight/competition and 550+ GSM for heavy-duty training. Additionally, verify that the collar is reinforced with EVA foam to prevent bacteria absorption and maintain shape, and that triple stitching is used at high-stress points like the armpits and side vents.