CAS 503-17-3 appears in our catalog under these names: 2-Butyne, 98% , 2-Butyne, 98%, 2-Butyne, >97.0%(GC), 2-BUTYNE, 99%. Offered by: Thermo Scientific (Alfa Aesar), Thermo Scientific (Acros), TCI, Sigma-Aldrich. Available pack sizes: 5g, 25g, 100g, 1g, 5ml.