The OTs-01 Kobalt (, "Cobalt") is a Russian double-action 9 mm revolver designed by Igor Stechkin and Boris Avraamov. The revolver was developed by TsKIB SOO from 1991 to 1992 and was meant for sale to the Ministry of Internal Affairs and to law enforcement. In 1992 it was adopted by Ministry of the Interior of the Russian Federation as service weapon under designation RSA (Revolver Stechkina-Avraamova). Since 1994 it was also manufactured by "Zlatoust Machine-Building Plant" and "Uralsk Machine-Building Plant" under designation TKB-0216 (ТКБ-0216).