These heavy duty ratchet pulleys have a suspension capacity of 75 lbs each. Two pulleys are provided per pack for a combined capacity of 150 lbs. Use them to suspend lighting fixtures over the growing area and adjust the height as needed. Or raise the lights up, out of the way, when watering. The clip-on carabiners allow for easy installation and removal. SunBlaster Hang Its are designed to work with any number of compatible SunBlaster products such as the Universal Hanger(not included), but we found they can easily adapt to work with other makes and brands. The extra strength and easy adjustability made changing the systems very simple.