diff --git a/api/s18_sources.py b/api/s18_sources.py
index d06a73a..42985a1 100644
--- a/api/s18_sources.py
+++ b/api/s18_sources.py
@@ -109,7 +109,7 @@ class InpSource:
         num_without_desc = (num - 1) if has_desc else num
 
         self.node = str(tokens[0])
-        self.s_type = float(tokens[1])
+        self.s_type = str(tokens[1])
         self.strength = float(tokens[2])
         self.pattern = str(tokens[3]) if num_without_desc >= 4 else None