It's highly likely that, if you're a follower of fashion, you at one point or another had a bucket list of designer bags you'd hope to one day have in your closet. Whether you're a Chanel 2.55 kind of person or more of a Céline trapeze devotee, there are a few luxury staples that have long been (and will continue to be) hot commodities on the market — some even climbing in value over the years, making the investment all the more tempting. The secondhand market has long been a nice entry point for shoppers looking to find their dream bag at a slight discount, or to track down an elusive, limited-release style that's been off shelves for seasons. Specialty sites like The Real Real, Vestiaire Collective, and Tradesy have made it all the easier to get your hands on gently-used luxury goods online. Still, when we find ourselves faced with a seemingly too-good-to-be-true deal, the fear sets in: Is this for real, or is it a knockoff?Over the years, we've all developed our tricks of the trade to avoid getting duped on designer handbags. especially since these purchase require a lot of penny-pinching and research. This week, Racked sat down with Graham Wetzbarger, director of authentication at The Real Real , to get a master class on spotting a fake designer bag. He focused on three particular styles that are historical favorites on the market: a Louis Vuitton monogram bag, a Chanel 2.55, and an Hermès Birkin.A lot of the authentication comes down to a few very minor but crucial manufacturing details that are unique to these fashion houses. There are four key features to pay attention to, according to Wetzbarger: materials, construction, hardware, brand-specific markings. For instance, Louis Vuitton leather goods come with a date code, which indicates when the piece was made; Hermès Birkins have similar craftsmanship markings, although they can be much more discreet. ("It's called a blind stamp because you might go blind looking for it," Wetzbarger says in the accompanying Facebook Live interview .) For Chanel bags, it can come down to those iconic crossed C's: Turns out, the way they're layered on each other is very much intentional — and you should always ensure "the right-facing C should cross over the left-facing C at the top, and under the left-facing C on the bottom," per Racked. Also, if the bag has that registered logo on it on a zipper or elsewhere? It's fake "100% of the time."