Reliable and robust RNA oligonucleotides with phosphodiester or phosphorothioate linkage. Phosphorothioate bonds are phosphodiester analogues in which non-bridging oxygen has been replaced by sulphur, increasing resistance against nuclease digestion.

Further modifications at the 3′ and 5′ ends are available including 6- Carboxyfluorescein, Amine, Biotin, Phosphate, Cholesterol, Thiol C6 S-S and Vitamine-E (Alpha-Tocopherol).