diff --git a/src/main/java/com/iqser/red/pdftronlogic/commons/InvisibleElementRemovalService.java b/src/main/java/com/iqser/red/pdftronlogic/commons/InvisibleElementRemovalService.java
index 6ce64e1..13f66e8 100644
--- a/src/main/java/com/iqser/red/pdftronlogic/commons/InvisibleElementRemovalService.java
+++ b/src/main/java/com/iqser/red/pdftronlogic/commons/InvisibleElementRemovalService.java
@@ -37,6 +37,7 @@ import lombok.extern.slf4j.Slf4j;
 public class InvisibleElementRemovalService {
 
     static public final double TOLERANCE = 1;
+    public static final String KNECON_OCR = "KNECON_OCR";
 
 
     /**
@@ -92,7 +93,7 @@ public class InvisibleElementRemovalService {
      */
     public void removeInvisibleElementsButKeepOcrText(InputStream pdfFile, OutputStream out, boolean delta) {
 
-        removeInvisibleElements(pdfFile, out, delta, true, Set.of("KNECON_OCR"));
+        removeInvisibleElements(pdfFile, out, delta, true, Set.of(KNECON_OCR));
     }
 
 
@@ -101,7 +102,7 @@ public class InvisibleElementRemovalService {
      */
     public void removeInvisibleElementsButKeepOcrText(PDFDoc pdfFile, boolean delta) {
 
-        removeInvisibleElements(pdfFile, delta, true, Set.of("KNECON_OCR"));
+        removeInvisibleElements(pdfFile, delta, true, Set.of(KNECON_OCR));
     }