diff --git a/reference/imagick/imagick/setcompression.xml b/reference/imagick/imagick/setcompression.xml
index bb27d35c6c..44dc999584 100644
--- a/reference/imagick/imagick/setcompression.xml
+++ b/reference/imagick/imagick/setcompression.xml
@@ -25,6 +25,7 @@
      <term><parameter>compression</parameter></term>
      <listitem>
       <para>
+       The compression type. See the <link linkend="imagick.constants">Imagick::COMPRESSION_*</link> constants.
       </para>
      </listitem>
     </varlistentry>