Based on your query, here is the information for the Zego Hot & Cold Stainless Steel Vacuum Insulated Flask:

This product appears to be a large capacity vacuum flask, designed for extended temperature retention.

Note on Availability:

While the specific 3L Black model is less commonly listed than the 4L or smaller Zego flasks in online searches, the brand and product line are available through various retailers, particularly in certain international markets. The 72-hour insulation claim is a key feature of this Zego product series.

You may need to check with local or specialized retailers to confirm the current stock and price of the 3L Black version.