RELAXED POPLIN SHIRT | Aritzia Sunday Best Size Medium Relaxed poplin button-up shirt-cool oversized fit, tried to wear but I am a small and just too big on me. Length at front is 32", back length is 34", chest flat is 24". Nice lightweight cotton poplin-grab this if you're a medium! orig $88 Refined season after season for that perfect relaxed look, this is a longsleeve button-up shirt with a front patch pocket and dropped shoulders. It's made from crisp, lightweight 100% cotton poplin with a smooth, airy feel.