diff --git a/ch.psi.fda.xscan/src/main/java/ch/psi/fda/core/loops/cr/MainHeader.java b/ch.psi.fda.xscan/src/main/java/ch/psi/fda/core/loops/cr/MainHeader.java
index f9a660a..c022563 100644
--- a/ch.psi.fda.xscan/src/main/java/ch/psi/fda/core/loops/cr/MainHeader.java
+++ b/ch.psi.fda.xscan/src/main/java/ch/psi/fda/core/loops/cr/MainHeader.java
@@ -1,5 +1,8 @@
 package ch.psi.fda.core.loops.cr;
 
+/**
+ * Header of the ZMQ message
+ */
 public class MainHeader {
 	private String htype;
 	private int elements;