CAS 203716-99-8 appears in our catalog under these names: Endosulfan-II-1,1,5,5-d4, 98 atom % D, min 98% Chemical Purity, beta-Endosulfan D4, beta-Endosulfan D4 100 µg/mL in Acetone, D4-beta-Endosulfan, D4-beta-Endosulfan, Concentration: 100 µg/ml Solvent: Acetonitrile. Offered by: CDN, Dr. Ehrenstorfer, HPC Standards. Available pack sizes: 0,01g, 0,005g, 10mg, 1ml, 1x5mg, 1x1ml.