White split urad is the hulled version, skin removed, pale and quick to cook. It is the dal that turns into batter.

This is what you buy for idli, dosa and vada.

Soak it, grind it, and it whips up into a light batter that traps air and ferments. Fried in a tempering it does another job entirely, turning golden and nutty. Two very different uses from one bag.

On the shelf at Curry Corner, North Melbourne.