This disclosure relates generally to a moisture curable composition. The composition includes a first, crosslinkable copolymer having a plurality of silyl alkoxy terminal groups and a backbone that is the reaction product of a diisocyanate and a mixture of a low molecular weight polyether polyol and a high molecular weight polyether polyol; a second crosslinkable oligomer having a plurality of silyl alkoxy terminal groups and a backbone that is the reaction product of a diisocyanate and a low molecular weight polyether polyol; and a third crosslinkable oligomer having a plurality of silyl alkoxy terminal groups and a backbone that is the reaction product of a diisocyanate and a high molecular weight polyether polyol.