diff --git a/src/pms.h b/src/pms.h
index a83ee20..71ff760 100644
--- a/src/pms.h
+++ b/src/pms.h
@@ -154,7 +154,7 @@ namespace pmsx {
 					5.0f,
 					10.0f,
 
-					0.0f
+					NAN
 				};
 				return DIAMETERS[min(Ofset + index, static_cast<decltype(Ofset + index)>(_countof(DIAMETERS)))];
 			}