CE4 V3 Clearomizer Spare Heads This is the replaceable component part of the CE4 V3 Clearomizer. These are very easy to install. Just unscrew the base at the bottom (opposite end to the mouthpiece), pull out the inner part (making sure there is no liquid inside the chamber prior to disassembling) unscrew the old head & replace with the new one. Vapouriz offer 5 different ohm rated heads for the CE4 V3. *1.8ohm *2.1ohm *2.4ohm *2.8ohm *3.2ohm The standard Vapouriz CE4 V3 Clearomizers come with 2.4ohm heads as standard. What do the different ohm ratings mean? Ohms are the measurement of the resistanceto electricity of an object. So when atomizer is 2.1 ohms that is the resistance measurement. Since a normal electronic cigarette battery puts out only 3.7 volts, you need a very low resistance to get the filament to heat up. The lower you go, the hotter it will get but there is a trade-off. The lower you go the more power the battery has toexpend to try & pass electricity through the filament, so the battery will not last as long. Since most electronic cigarette batteries have to run as 3.7 volts, you have to find an ohm value that will get hot enough to produce vapour at the right temperature & not kill the battery in a few minutes. With 3.7 volts, that just happens to be around 1.8 to 3.2 ohms for an atomizer value. Less than that & your battery will deplete faster. More than that & vapour production will be diminished. Product Care Clearomizers & replacement heads last approximately 1-3 weeks & are consumable items. We offer a 7 day warranty on all clearomizers. Please dispose of this product in an appropriate manner.