Essential is such a beautiful word. Indispensable, crucial, fundamental, imperative, it describes them all.
ATA has a jacket that we consider to be essential.
Once, in the 1940's when Erich Müller needed a jacket, he painted one for himself, and said it must be called essential. We borrowed the name and were inspired by it (as that jacket had short sleeves).
Our ATA jacket is more like a " la veste de travail", a blue French work jacket which was owned by almost every worker worldwide.
Our essential jacket is sturdy, made of drill, a cotton fabric with a diagonal weave, and has four pockets: three external pockets and an inner pocket.