These are the spects for the 1510.
SPECIFICATIONS
GU-1510-06-WPDF Waterproof Injection Molded Case
[ul]
[li]Interior Dimensions[/li]

[li]Interior Length: 15"[/li]

[li]Interior Width: 10.5"[/li]

[li]Interior Height: 6.2"[/li]

[li]Exterior Dimensions[/li]

[li]Exterior Length: 16.7"[/li]

[li]Exterior Width: 13.4"[/li]

[li]Exterior Height: 6.8"[/li]

[li]Exterior Weight: 5.8lb.[/li]

[/ul]
How is that larger?