The OXBAR 35K contains nicotine at a concentration typically around 5% (50mg/ml). This is considered to be a high nicotine level, suitable for users who are looking for a strong hit. It is ideal for experienced vapers or those who are transitioning from smoking, as it provides a more intense nicotine experience compared to lower concentrations. It's important to note that nicotine strength should be chosen based on individual preference and tolerance.