Simpson Strong-Tie Hurricane Ties Provide resistance to uplift and lateral forces. They are designed to help counter the effect of high winds and seismic events on a structure. The H2.5A is also used for general tie purposes, strongback attachments, and as an all-purpose tie where 1 member crosses another. For use, install in pairs to connect 2x rafter to top plate. H2.5A Hurricane Tie, Designed For Easy Installation, Designed To Help Counter Extreme Winds Generated By Nature, Provides Resistance To Uplift & Lateral Forces, Install In Pairs To Connect 2 x Rafter To Top Plate, Install With Five 8D x 1-1/2" Nails To Rafter, 5-8D x 1-1/2"