1998GOST 6942-1998 Cast iron waste pipes and fitings. Specifications
1980GOST 6942.21-1980 Cast iron waste pipes and fittings. Double branches, two-planar. Construction and dimensions
0000 GOST 6942.27-1969
GOST 6942.21-1980 Cast iron waste pipes and fittings. Double branches, two-planar. Construction and dimensions was changed to GOST 6942-1998 Cast iron waste pipes and fitings. Specifications.