Appeal by petitioners from an order of the County Court, Suffolk County (Cacciabaudo, J.), dated January 12, 1984, which denied their motion pursuant to CPLR 2304 to quash a Grand Jury subpoena duces tecum upon the ground that it is constitutionally overbroad. H Order affirmed, without costs or disbursements. 1 Because petitioners did not produce any concrete evidence that the subpoenaed documents had no conceivable relevance to the Grand Jury investigation, they failed to overcome the subpoena’s presumption of validity (see Virag v Hynes, 54 NY2d 437; Matter of Horowitz, 482 F2d 72; Matter of Doe v Kuriansky, 91 AD2d 1068). Accordingly, the County Court properly denied petitioners’ motion to quash the subpoena. Lazer, J. P., Man- . gano, Gibbons and Niehoff, JJ., concur.