Yep, you need them that heavy to jump off equipment. Those cheapo's wouldn't hold up, they would heat up and melt.Those didn't come in a bag, but I would have used it for something else if they did.
Some days I'd change trucks 2 or 3 times and none of them were my truck so everything got transferred each time. They jumped off a matric ton of excavators, bulldozers, loaders, and old junk onsite dump trucks.