CAS 15988-11-1 appears in our catalog under these names: 4-Phenylurazole, 98+% , 4-Phenylurazole, >98.0%(T), 4-Phenylurazole 95%, 4-PHENYLURAZOLE, 98%, 4-Phenyl-1,2,4-Triazolidine-3,5-Dione, 98%, 98%. Offered by: Thermo Scientific (Alfa Aesar), TCI, Ambeed, Sigma-Aldrich, Chemat. Available pack sizes: 5g, 25g, 100g, 1g, 10g, 5kg, 25 g.