diff --git a/src/libslic3r/PrintConfig.cpp b/src/libslic3r/PrintConfig.cpp
index 37b85b4fee..404eb20e55 100644
--- a/src/libslic3r/PrintConfig.cpp
+++ b/src/libslic3r/PrintConfig.cpp
@@ -2220,6 +2220,7 @@ void PrintConfigDef::init_fff_params()
     def->enum_values.push_back("BVOH");
     def->enum_values.push_back("PCTG");
     def->enum_values.push_back("EVA");
+    def->enum_values.push_back("FLEX");
     def->enum_values.push_back("HIPS");
     def->enum_values.push_back("PA");
     def->enum_values.push_back("PA-CF");