This is a Mizuno Techfill jacket. It's a size S. It's warm because it has padding. I bought it around February of this year, but I'm selling it because the size didn't fit. How about it for training or running? I've only used it twice, so the condition is quite good, but it is a used item, so please understand. A hybrid item that utilizes lightweight and highly insulating Techfill and also considers ease of movement. ■Product Features A hybrid jacket that uses Techfill for the front and back body, and Techshield for both sleeves and sides. Uses ventilation zippers on the chest. Water-resistant and machine washable. About this product Hybrid jacket using Techfill for the front and back body, and Techshield for both sleeves and sides. Uses ventilation zippers on the chest. Water-resistant and machine washable. The moisture-absorbing and heat-generating material "Breath Thermo" absorbs moisture generated by the human body and generates heat, providing comfortable insulation. Achieves quick drying and heat retention. High-performance insulation, Techfill. Color: Navy Size: S Track and Field Running Training