In The Sandman - both the comic and the new Netflix adaptation - Morpheus, Dream of the Endless, takes some of his power and invests it into three tools: a pouch of sand, a helm he made from the bones of a dead god, and a ruby, sometimes called the dreamstone or by other names.

There are hints of each tool’s powers, but they’re not drawn very distinctly. The sand of the comics primarily gives incredibly vivid dreams, and also allows Dream to locate his helm in Hell; in the series it also transports him from one realm to another. The helm’s powers are vague, though in the series it seems to grant the ability to see what Dream desires. The ruby is described in the series as having the power to make dreams real, but in the comics Doctor Destiny uses it to manipulate only dreams, both on a worldwide scale and more directly of those near him.

I’ve read most of the comics - certainly the full main run - but it’s been a while. I don’t remember this ever being explained beyond Dream vaguely saying he created them to help him in his duties. But it seems pretty clear he doesn’t really need any of them - he can do everything they “helped” him do on his own once he reabsorbs the power he put into them (as seen with the ruby at the end of Preludes & Nocturnes). The other Endless have their sigils, but aside from Destiny’s book, they don’t seem to need any tools - or, most of the time, even to actively do anything - to fulfil their roles.

So: what are the actual powers and purposes of Dream’s tools? And why did he create them?

I’m primarily interested in an answer that draws on the comics, but if I’ve missed something in the series I’m also interested in an answer based on that. And I’m also happy to have it confirmed that the specifics were never revealed, which I suspect is the case, but I’ve not been able to determine.