エコフレンドリースタッカーカップ

My toddler loves pouring water between these in the bath, and the fact that each cup holds exactly the right amount makes it easy to teach him about "more" and "less." The numbers on the bottom are a nice touch too, so he's starting to recognize them while he plays.

The numbers printed on the bottom are perfect for sneaking in a bit of counting practice during bath time, and the cups nest together so neatly they don’t take up half the toy basket. We use them for water play almost daily and they’ve held up to plenty of being chewed on, too.

My 10-month-old loves stacking these up and knocking them over, though the numbers wear off a bit faster than I'd like. The graduated sizes are perfect for little hands, and they're great for water play in the bath.