The present invention provides a Fischer-Tropsch gasoil fraction having: (a) an initial boiling point of at least 250° C.; (b) a final boiling point of at most 350° C.; (c) a kinematic viscosity at 25° C. according to ASTM D445 of from 4.0 to 4.6 cSt; and (d) a flash point according to ASTM D93 of at least 117° C. In another aspect the present invention provides a composition and the use of a Fischer-Tropsch gasoil fraction according to the invention.