As I understand it the correct title is 16 sq which refers to the sail size in meters.
Here are the boat specs.
Length 5.0m
Beam 2.5m
Sail Area 16 sq m
Weight 130kg
Designer Ross Guinea

However it has also been unofficially referred to as 16ft sq the ft most likely refers to the length in this case, but I can't be certain.

The 14 sq specs

Length 4.5m
Beam 2.44m
Sail Area 14 sq m
Weight 105kg
Designer Ross Guinea