IOTA 233 (CAS No. 68952-30-7) is hydrogen-terminated T-type phenyl polysiloxane with molecular weight ranging from 550 to 3000. Its viscosity can be selected from 5 to 5000 mm²/s, and hydrogen content is adjustable between 0.35% and 0.75% to satisfy various formulation demands. It is a colorless transparent viscous liquid with specific gravity of 1.00–1.01 and refractive index of 1.46–1.52 at 20°C. It boasts excellent compatibility with dimethyl silicone oil, liquid silicone rubber, phenyl silicone rubber and phenyl silicone resin, achieving homogeneous mixing without delamination and requiring no extra compatibilizers. Its flash point exceeds 110°C for low volatilization and safe processing. It cures via hydrosilylation through reactive Si-H groups, serving as a standard crosslinker for addition-cure silicone rubber, phenyl silicone rubber and phenyl silicone resin. Packed in 15kg and 200kg coated iron drums and stored in cool, ventilated warehouses, it fits large-scale industrial formulation, simplifies raw material selection and cuts formula debugging costs.