Initially, when getting into the world of vaping, newcomers may not consider the significance of a mouthpiece. However, the sensation of a mouthpiece on the lips is paramount and becomes of greater importance with continued use. Due to the wide variety of types and sizes available, it may be difficult for some vapers to determine which options are best suited for their devices.
As vaping progressed, the technology behind mouthpieces evolved, no longer limited to built-in or proprietary (brand-specific) designs. The RBA (rebuildable atomizer) market was one of the key contributors to the development of various mouthpiece designs, popularizing the term "drip tip". These enthusiasts were classified as either "flavour chasers" or "cloud chasers", while the majority found themselves somewhere in the middle, where most remain today.
Advanced users, or cloud chasers, who utilized RDAs (rebuildable drip atomizers), would often use bored-out 510 mouthpieces due to the sheer heat that was often being produced. These larger-diameter holes in the mouthpiece not only allowed more airflow but also allowed vapers to drip e-liquid directly into the wicking material without having to remove the top cap of the RDA, giving birth to the phrase "Drip Tip". As technology advanced, the requirement for wider tips with greater airflow grew ever more apparent, and the 810 Drip Tip subsequently became a secondary standard.
Those who prioritize taste often opt for 510 tips, as they feature narrower pathways, resulting in a more concentrated flavour stream. Shorter tips provide a warmer vapor, whereas longer tips cause the vapor to cool as it travels, potentially impacting the strength of the flavour as it mixes with more air.
Most modern tanks with removable mouthpieces will use either a 510 or 810 mouthpiece, with the exception of a few tanks utilizing proprietary designs. While some will likely be able to tell just by looking, even experts in the vaping community may find themselves mistaken on occasion. Measuring the diameter of the mouthpiece's base, or the opening in the tank where the mouthpiece goes, should be the first and last step needed to determine whether a 510 or 810 mouthpiece can be used.
Be sure not to include the O-rings in the measurement.
If the measurement isn't one of the two listed above, it likely means that a proprietary size is being used, which may present challenges when searching for a replacement. While not much can be done to make a 510 or 810 mouthpiece work with proprietary sizes, adapters do exist to make 510 mouthpieces work in 810 fittings, and vice versa.
Knowing which size to use is often only half the battle; the rest comes down to the best form, function, fit, and finish to best suit personal preferences.