Easy Breath lab coats are a medium weight 3-layer SMS material. It still offers fluid resistance with a more light weight material.

SMS provides a fluid and particulate barrier to protect the worker without sacrificing mobility and comfort. 
Garments constructed of SMS fabric are strong and durable, yet offer outstanding comfort, breathability, softness, and wearable. 
SMS is lightweight and resistant to tears and punctures. SMS barrier fabric is a unique trilaminate construction that offers a high tensile strength and toughness that is also soft, durable, and easy to work with.