RVCA "That'll Do" Slim Fit Long Sleeve Shirt

I've been wearing RCVA button-ups since the mid-aughts and their medium sized shirts have always fit me perfectly. They hold up really well and seem to break-in perfectly. I really am curious about how they landed on this precise formula and then decided it was the one, but the fabric consists of 53% cotton/44% polyester/3% elastane.