Order, entered on September 12, 1960, denying motion to stay an arbitration, or in the alternative, to limit and define the issues to be arbitrated, unanimously affirmed, with $20 costs and disbursements to the respondents. Special Term properly concluded that petitioner-appellant was barred from attacking the validity of the contract because of participation in the selection of the arbi*468trators and in the arbitration proceeding. We have nevertheless examined into appellant’s contention that the contract containing the arbitration clause is not valid or enforcible, and have concluded that the contract contains all the essential elements necessary to indicate that the parties entered into a binding obligation. There is nothing illusory about the promises in the agreement. Finally, the demand for arbitration sufficiently defines the issues to be arbitrated. Settle order giving appellant seven days after service thereof with notice of entry within which to file with the American Arbitration Association his selection of arbitrators and his answer. Concur — Valente, J. P., McNally, Stevens and Eager, JJ.