CA: http://ncix.com/search/?categoryid=0&q=corsair+sp+fan
US: http://us.ncix.com/search/?categoryid=0&q=corsair+sp+fan

Optimized for static pressure means that these fans perform better than others in situations where there is a significant airflow obstruction such as on a heatsink or radiator. They will also perform better with fan filters or restrictive grilles compared to their AF series brethren