They are different formulations
Salt nicotine and freebase e-liquids are different product types and are commonly sold in different nicotine strengths. Always read the strength, bottle size and other information printed on the product label before use.
Device compatibility matters
Not every liquid is suited to every device, pod or coil. Follow the device and coil manufacturer guidance and do not assume that a liquid used in one setup is automatically appropriate for another.
Check the label instead of guessing
The bottle label should be your source for nicotine strength, manufacturer information and usage warnings. Avoid using unlabelled liquid or moving liquid into containers that make the contents difficult to identify.
Store e-liquid carefully
Keep bottles closed, away from excessive heat and direct sunlight, and out of reach of children and pets. Follow the storage instructions printed by the manufacturer when they are provided.