This is a rubber pipe that goes from the brake fluid reservoir to the master cylinder on a classic Fiat 500.
If you're restoring or maintaining one of these little Italian cars, this is the hose you need to replace that old, cracked original.

It's unbranded but made of quality rubber, and it's a new part so it'll be soft and flexible – not hard and brittle like the one that's been under the hood for decades.

No manufacturer part number or UPC on this one, but it's pretty straightforward.