A moisture curable composition capable of cure to an elastomeric body, comprising a polymeric material having not less than two hydroxyl or hydrolyzable groups an alkoxysilane curative and a catalyst comprising: a mixture and/or reaction product of a compound (i) M[OR]4 and compound (ii) M[OR′]x[Z]z, wherein M represents a metal having a valency of 4 selected from Group IVB of the Periodic Table, preferably titanium or zirconium. Each R and R′ may be a primary, secondary or tertiary aliphatic hydrocarbon or the group SiR93; and a compound iii) of the general formula A-C(═O)R1—C(═O)—B wherein R1 is a methylene group or a substituted methylene radical, A is selected from —(CX2)nC(R2)3 wherein n is from 0 to 5, and an adamantyl group or a derivative thereof; B is selected from the group of —(CX2)tC(R2)3 wherein t is from 0 to 5; a monovalent alkyl group having from 1 to 6 carbon atoms and; OR3, wherein R3 is selected from the group of —(CX2)tC(R2)3 and a monovalent alkyl group having from 1 to 6 carbon atoms; wherein each X is the same or different and is selected from the group of a halogen radical and hydrogen, each R2 is the same or different and is selected from the group of a halogen radical and an alkyl radical having one to eight carbon atoms, and when n is greater than 0 at least one of X or R2 is a halogen radical