FL-series
The FL-series was designed as land-based counterparts to the SY-series, and had a much longer production run than the SY-series. The FL-series was less expensive since it did not have to deal with more demanding conditions at sea. An added benefit was the ability to locate the missiles separately from the targeting and control systems, which improved survivability and flexibility. The SY-, HY-, and FL-series all shared the same systems.
A supersonic version, the FL-7, was also developed but differed significantly from the SY-series and its immediate derivatives.
Read more about this topic: Silkworm (missile)