Features: Used to sense the level of liquid within a tank. Light weight and simple working principle, high reliability. The switch may activate a pump, an indicator, an alarm, or other device. This float switch is a simple structure, easy installation liquid level controller. Widely used in electronic, electrical, chemical, water treatment, drainage and other fields. The versatility of this vertically mounted sensor means that it can be installed either at the top or base of your tank, depending on whether you for wish to detect the water's rise or fall. Package Included: 1 x Floating Switch 6 Size Optional: 100mm / 3.94 inch 150mm / 5.91 inch 200mm / 7.87 inch 250mm / 9.84 inch 300mm / 11.81 inch 400mm / 15.75 inch Instruction is not included. Any questions, please contact us for solution. Hope a nice day! Notice: - Please allow slight dimension difference due to manual measurement. - Please consider the actual sizes in the listing as the pictures are generally enlarged to show detail. - Due to different producing batches, product details might be a little different. If you minding the difference, please buy it carefully. - Due to the light and screen difference, the item's color may be slightly different from the pictures. Thanks for your understanding.