These replaced another system I had which was bulky and messy (basically a tray I had to fill with sand). These are four weights about 30lbs. each. No filling up with sand or water!!  Super easy to put together. Just take out of box and lay on the T portion of your umbrella pole. They take up less space (than my previous system) and lay completely flat. Only gave 4 stars because I've only had for a week and time will tell. Also these were priced higher on other sites.