These high quality Ultra Mesh harness vests are made with softer, more flexible and breathable poly meshh. It has more tensile strength and resistance to wear and uses Kam buckle with 4-point technology. It has four point locking, quick release clasp and a adjustable chest strap for flexibility and a better fit. A harness vest is much more comfortable for your baby than a collar as it pulls on their chest & not on their neck.