While the US and Western Europe rely on the 300×250 rectangle, Eastern Europe (Russia, Ukraine, and CIS countries) relies on the 240×400 Vertical Rectangle. It is one of the most popular sizes on the Yandex advertising network.
Its slimmer profile allows it to fit into tighter sidebars, but its extra height (400px) gives it more vertical presence than the standard Medium Rectangle.
Why Use the 240×400?
1. Sidebar Efficiency
Many older website layouts use narrow sidebars (under 250px). The standard 300px wide ad won’t fit, but the 240×400 slides in perfectly, maximizing revenue from tight spaces.
2. Vertical Storytelling
The 400px height makes this unit excellent for “listicle” style ads or displaying a vertical product shot (like a bottle or a smartphone) in its entirety.
Conclusion
If your traffic comes from Eastern Europe or you are working with older site layouts, the 240×400 is an essential unit to have in your inventory.