The Heavy '95s were equipped with cross-body strakes that provided better heat dissipation via redistributing the heat dissipation of the strakes through a wider area; this also allowed for more weight to be carried, giving them the nickname Heavy '95.
The Heavy-95 was developed by the Rebel Alliance early during the Galactic Civil War, before the X-wing starfighter was available. In large part due to the success of the Heavy '95s production, the Alliance also developed the advanced X-wing fighter.