diff --git a/src/main/java/org/kohsuke/github/GHBranch.java b/src/main/java/org/kohsuke/github/GHBranch.java
index f4e90f655..4c80db9ef 100644
--- a/src/main/java/org/kohsuke/github/GHBranch.java
+++ b/src/main/java/org/kohsuke/github/GHBranch.java
@@ -7,6 +7,8 @@ import java.io.IOException;
 import java.util.Arrays;
 import java.util.Collection;
 
+import static org.kohsuke.github.Previews.LOKI;
+
 /**
  * A branch in a repository.
  * 
@@ -81,9 +83,7 @@ public class GHBranch {
     }
 
     private void setProtection(BranchProtection bp) throws IOException {
-        new Requester(root).method("PATCH")
-                .withHeader("Accept","application/vnd.github.loki-preview+json")
-                ._with("protection",bp).to(getApiRoute());
+        new Requester(root).method("PATCH").withPreview(LOKI)._with("protection",bp).to(getApiRoute());
     }
 
     String getApiRoute() {
diff --git a/src/main/java/org/kohsuke/github/GHLicense.java b/src/main/java/org/kohsuke/github/GHLicense.java
index 283a60edf..47bec0f71 100644
--- a/src/main/java/org/kohsuke/github/GHLicense.java
+++ b/src/main/java/org/kohsuke/github/GHLicense.java
@@ -32,6 +32,8 @@ import java.net.URL;
 import java.util.ArrayList;
 import java.util.List;
 
+import static org.kohsuke.github.Previews.DRAX;
+
 /**
  * The GitHub Preview API's license information
  * <p>
@@ -141,9 +143,7 @@ public class GHLicense extends GHObject {
     protected synchronized void populate() throws IOException {
         if (description!=null)    return; // already populated
 
-        root.retrieve()
-                .withHeader("Accept","application/vnd.github.drax-preview+json")
-                .to(url, this);
+        root.retrieve().withPreview(DRAX).to(url, this);
     }
 
     @Override
diff --git a/src/main/java/org/kohsuke/github/GHRepository.java b/src/main/java/org/kohsuke/github/GHRepository.java
index 04e2b8510..472adf41e 100644
--- a/src/main/java/org/kohsuke/github/GHRepository.java
+++ b/src/main/java/org/kohsuke/github/GHRepository.java
@@ -51,6 +51,7 @@ import java.util.Set;
 import java.util.TreeMap;
 
 import static java.util.Arrays.asList;
+import static org.kohsuke.github.Previews.DRAX;
 
 /**
  * A repository on GitHub.
@@ -878,7 +879,7 @@ public class GHRepository extends GHObject {
     private GHContentWithLicense getLicenseContent_() throws IOException {
         try {
             return root.retrieve()
-                    .withHeader("Accept","application/vnd.github.drax-preview+json")
+                    .withPreview(DRAX)
                     .to(getApiTailUrl("license"), GHContentWithLicense.class).wrap(this);
         } catch (FileNotFoundException e) {
             return null;
diff --git a/src/main/java/org/kohsuke/github/GitHub.java b/src/main/java/org/kohsuke/github/GitHub.java
index dff5f5914..e5bf16b1d 100644
--- a/src/main/java/org/kohsuke/github/GitHub.java
+++ b/src/main/java/org/kohsuke/github/GitHub.java
@@ -27,6 +27,7 @@ import static com.fasterxml.jackson.annotation.JsonAutoDetect.Visibility.ANY;
 import static com.fasterxml.jackson.annotation.JsonAutoDetect.Visibility.NONE;
 import static java.util.logging.Level.FINE;
 import static java.net.HttpURLConnection.HTTP_UNAUTHORIZED;
+import static org.kohsuke.github.Previews.DRAX;
 
 import java.io.ByteArrayInputStream;
 import java.io.FileNotFoundException;
@@ -353,9 +354,7 @@ public class GitHub {
     public PagedIterable<GHLicense> listLicenses() throws IOException {
         return new PagedIterable<GHLicense>() {
             public PagedIterator<GHLicense> _iterator(int pageSize) {
-                return new PagedIterator<GHLicense>(retrieve()
-                        .withHeader("Accept","application/vnd.github.drax-preview+json")
-                        .asIterator("/licenses", GHLicense[].class, pageSize)) {
+                return new PagedIterator<GHLicense>(retrieve().withPreview(DRAX).asIterator("/licenses", GHLicense[].class, pageSize)) {
                     @Override
                     protected void wrapUp(GHLicense[] page) {
                         for (GHLicense c : page)
@@ -378,9 +377,7 @@ public class GitHub {
      */
     @Preview @Deprecated
     public GHLicense getLicense(String key) throws IOException {
-        return retrieve()
-                .withHeader("Accept","application/vnd.github.drax-preview+json")
-                .to("/licenses/" + key, GHLicense.class);
+        return retrieve().withPreview(DRAX).to("/licenses/" + key, GHLicense.class);
     }
 
     /**
diff --git a/src/main/java/org/kohsuke/github/Previews.java b/src/main/java/org/kohsuke/github/Previews.java
new file mode 100644
index 000000000..a5d061cbd
--- /dev/null
+++ b/src/main/java/org/kohsuke/github/Previews.java
@@ -0,0 +1,9 @@
+package org.kohsuke.github;
+
+/**
+ * @author Kohsuke Kawaguchi
+ */
+/*package*/ class Previews {
+    static final String LOKI = "application/vnd.github.loki-preview+json";
+    static final String DRAX = "application/vnd.github.drax-preview+json";
+}
diff --git a/src/main/java/org/kohsuke/github/Requester.java b/src/main/java/org/kohsuke/github/Requester.java
index 43c4e0769..ac492579c 100644
--- a/src/main/java/org/kohsuke/github/Requester.java
+++ b/src/main/java/org/kohsuke/github/Requester.java
@@ -110,6 +110,10 @@ class Requester {
         return this;
     }
 
+    /*package*/ Requester withPreview(String name) {
+        return withHeader("Accept",name);
+    }
+
     /**
      * Makes a request with authentication credential.
      */