These poly mailers are great. They're thick and sturdy, not flimsy at all, and the self-seal strip sticks really well. The 14.5x19 size is perfect for shipping clothes — I've used them for jackets, sweaters, hoodies, and bundles, and everything fits with room to spare without tearing or stretching out.
You get 100 in the pack, so it's a great value, and they look clean and professional when they arrive. I use them for all my Vinted and Depop orders now and I haven't had a single one rip or come open in transit. Highly recommend if you ship a lot.