Candela, YAG, LightSheer, Soprano—these are just a few of the hair-removal-laser brand names you might stumble across on your average medi-spa website. Companies like to name-drop the type of technology they use, but aren’t always so quick to explain what makes one laser different from another. This is part of the reason why it can be hard to understand what the best laser hair-removal device is for your hair and skin type.

Below, we’ve provided a quick breakdown of four common hair-removal lasers and identified pros and cons for each. The list is by no means exhaustive, but it may help you make a more informed decision.

Nd:YAG Laser

For dark skin

How it works: The Nd:YAG Laser is the preferred system when it comes to hair removal for dark skin because it has weaker melanin absorption. Melanin refers to the dark pigment in both skin and hair, and some lasers cannot tell the difference between the melanin in hair and the melanin in dark skin. This means they have the potential to injure the skin. The Nd:YAG laser, on the other hand, is safe for dark skin because of its long wavelengths, which penetrate past the melanin in the epidermis to the melanin in the hair. This seeking out of dark melanin is why, like most of the lasers on this list, it is still not very effective on fine or white hair.

Pros: The Nd:YAG has longer wavelengths than other hair-removing lasers, meaning that in addition to being safe for dark skin, it has the most potential to destroy hair at the papilla (the very bottom of the shaft).

Cons: Because it absorbs less melanin, it requires more treatments for optimal results. Treatments with YAG lasers can also be more painful and less effective on fine hair.

Common brand names: Cutera CoolGlide, Cynosure Elite, Candela GentleYAG

Alexandrite Laser

For olive skin

How it works: This laser has a slightly longer wavelength than some of its competitors (though not as long as the Nd:YAG), which makes it useable on a wide range of skin tones, including olive skin.

Pros: Perhaps the Alexandrite’s most important benefit is an increased spot size and repetition rate, which means it can treat a larger area of skin, faster. This makes it one of the quickest hair-removal lasers available.

Cons: Despite its long wavelength, it still achieves a high melanin absorption, so there is a significant risk for discoloration and burns on all but very light skin.

Common brand names: Candela GentleLase, Cynosure Apogee, EpiTouch Plus

Diode Laser

For fair to medium skin

How it works: The Diode, one of the newest and most commonly used laser systems today, was designed for fair to medium skin types.

Pros: The Diode mixes both shorter and longer wavelengths, so it is both good at absorbing melanin and also penetrates deep into the hair follicles. The longer wavelengths also decrease the risk of skin damage.

Cons: The main drawback to the Diode laser is its newness, as there is not yet an appropriate amount of data to assess its long-term results.

Common brand names: LightSheer, SLP 1000, LaserLite, SopranoXL

Ruby Laser

For very light skin

How it works: As the oldest type of hair-removal laser, the Ruby has a higher melanin absorption rate than most other lasers on the market, making it most appropriate for very light skin and light hair removal.

Pros: Effective, even on very fine hair.

Cons: Because of the high melanin absorption, it is more prone to leave skin discolored. For this reason, it should only be used on very fair skin.

Common brand names: Palomar E2000, RubyStar