Abstract: A moisture curable sealant composition comprising an organopolysiloxane (A) containing reactive hydroxyl or hydrolysable groups bonded to silicon, a crosslinking agent (B) containing hydrolysable groups reactive with the reactive groups of (A) in the presence of moisture, the hydrolysable groups of (B) releasing an acid in the presence of moisture, a metal-containing catalyst for the reaction of the reactive groups of (A) with the hydrolysable groups of (B), and a filler, characterized in that the filler comprises calcined kaolin and is free of any other reinforcing filler and methanol and in the fact that the composition upon curing has a elongation at break of more than 250% and is non sagging.