As a general rule, when you enter a marijuana dispensary, flower products fall under one of three categories: low-, mid-, and top-shelf. These classifications are designed to reflect quality, and they’re priced accordingly. But what do these cannabis types really mean?

If you’re new to the world of legal cannabis, a word of advice: don’t always trust labels. Not every dispensary operates in good faith or possesses the information needed to make these qualitative distinctions.

“In most cases, labels like low-, mid-, and high-grade are sales tools to present an easy to understand sales strategy like a car salesman does—such as, how much do you want to spend on a car?,” Sean Black, High Times’ Cannabis Cup competition director, told High Times. “There are more meaningful sales descriptions that can inform a buyer of the cannabis’ quality… Labels such as private reserve, special stock etc are merely sales tools to indicate higher prices.”

“Be wary of gimmicks and theatrics,” Black said. “The plant should speak for the quality—and anything that says they’re the greatest or best in packaging generally tends not to be. Growers that are passionate and great at what they do are too focused and busy for smoke and mirrors.”

There are plenty of guides out there that attempt to help navigate users toward high-quality products based on various physical and chemical characteristics, but insiders will tell you that your most important asset when you visit a dispensary is your nose.

“The biggest thing I’m looking for [in a top-shelf strain] is a distinct sense of smell,” said Jake Browne, co-founder of The Grow-Off and The Denver Post’s first pot critic. “Jars should smell distinctly different from other jars, and there should be a number of terpenes that you can identify from whatever sample is out.”

That said, it’s often the case that “display notes” aren’t frequently changed, Browne said, so he recommends asking your budtender to give the flower a little pinch “to release some of those terpenes and help you get a better idea of what the actual smell of the strain is.”

That sentiment was echoed by Max Montrose, president of the cannabis education and certification company Trichome Institute. “Pungency comes first,” said Montrose. While you should absolutely use your eyes to identify red flags like mold, “you’re determining quality based on the smell first.”

Besides smell, visuals do matter when you’re looking for top-shelf bud.

Bright, robust coloration in a given stain generally signals a high-quality product. Top-shelf flower tends to be some combination of green and purple. Even for marijuana that’s grown outdoors, which makes it prone to tanning, you still want to see some flairs of green and overall brightness. When the weed on the shelf is brown, red, or yellow, that’s not a great sign, Montrose said. “You should really consider not purchasing it.”

If your dispensary provides magnification devices to inspect the product, you might also consider checking out the trichomes—the collection of crystalline hairs that aren’t always immediately visible to the naked eye. It might take some research or guidance if you’re a novice, but one way to determine the quality of a strain is to evaluate whether those small hairs on the plant are intact or “machine-trimmed and hacksawed down,” Browne said.

Once you can tell apart a low-quality strain from a high-quality strain, what do you make of mid-shelf bud?

In the absence of industry-wide standards for classifying low-, mid-, and top-shelf marijuana, I’ll defer to the experts. Montrose questioned dispensaries that sold “low-shelf” marijuana—simply because it carries a negative connotation.

“Usually businesses are good to have a top-tier and a mid-tier, but not to ever suggest to their customers that they’re offering something to them that’s a low-tier,” he said. “My personal opinion on it is, if you do see a low-shelf, that’s called the ‘bullshit, get-rid-off-it shelf because it’s near its expiration date or it has something wrong with it and so get it out of here.'”

But Browne sees some utility in the mid-shelf classification. He said that it comes down to how the cannabis is cured.

“A properly cured mid-shelf will still bounce back almost like you were squeezing a slightly stale marshmallow,” he said. It will still have a distinct smell, as opposed to smelling like either wet grass, hay, a damp basement, or fertilizer. Those are my big four stay-aways.”