1. Breathable mesh design, comfortable and not stuffy 2. The buckle is firm, it is not easy to break free, and travel is safe 3. Telescopic buckle design, easy to adjust the size, simple and practical, durable 4. Alloy thickened hook design, finely polished, wear-resistant and pull-resistant 5. Material: polyester fabric, metal buckle, plastic buckle 6. Size: S/M/L/XL 7. Bust: S about 34cm, M about 39cm, L about 46cm, XL about 57cm 8. Neck circumference: S about 324cm, M about 30cm, L about 34cm, XL about 38cm 9. Weight: S about 50 grams, M about 65 grams, L about 70 grams, XL about 80 grams