A Mechanical Mod is an unregulated device. This means that there is no circuitry in the Mechanical Mod to keep the voltage regulated during the life of the battery. Because you are taking power straight from the battery, there is no way to increase or decrease the voltage so the vapour production will eventually reduce until the battery dies. Due to their simplicity Mechanical Mods last a long time, longer than Regulated Mods that have lots of electrics and wiring. These devices are ideal for the advanced vaper and available now with Free UK and World Wide Delivery.