diff --git a/src/main/kotlin/info/mking/k2zpl/builder/Extensions.kt b/src/main/kotlin/info/mking/k2zpl/builder/Extensions.kt
index 6af63df..40889ca 100644
--- a/src/main/kotlin/info/mking/k2zpl/builder/Extensions.kt
+++ b/src/main/kotlin/info/mking/k2zpl/builder/Extensions.kt
@@ -3,7 +3,6 @@
 package info.mking.k2zpl.builder
 
 import info.mking.k2zpl.command.EndFormat
-import info.mking.k2zpl.command.FieldData
 import info.mking.k2zpl.command.LabelLength
 import info.mking.k2zpl.command.PrintQuantity
 import info.mking.k2zpl.command.StartFormat
@@ -11,14 +10,6 @@ import info.mking.k2zpl.command.ZplCommand
 import info.mking.k2zpl.command.options.ZplFont
 import info.mking.k2zpl.command.options.ZplYesNo
 
-/**
- * Adds field data.
- * @param data The data to be added to the field.
- */
-fun ZplBuilder.fieldData(data: String) {
-    command(FieldData(data))
-}
-
 /**
  * Sets the print quantity and related parameters.
  * @param quantity The number of labels to print.
diff --git a/src/main/kotlin/info/mking/k2zpl/builder/ZplBuilder.kt b/src/main/kotlin/info/mking/k2zpl/builder/ZplBuilder.kt
index 9925178..a733790 100644
--- a/src/main/kotlin/info/mking/k2zpl/builder/ZplBuilder.kt
+++ b/src/main/kotlin/info/mking/k2zpl/builder/ZplBuilder.kt
@@ -5,6 +5,7 @@ package info.mking.k2zpl.builder
 import info.mking.k2zpl.command.CustomCommand
 import info.mking.k2zpl.command.Font
 import info.mking.k2zpl.command.ZplCommand
+import info.mking.k2zpl.command.fieldData
 import info.mking.k2zpl.command.fieldOrigin
 import info.mking.k2zpl.command.fieldSeparator
 import info.mking.k2zpl.command.font
diff --git a/src/main/kotlin/info/mking/k2zpl/command/BarCode.kt b/src/main/kotlin/info/mking/k2zpl/command/BarCode.kt
index baea248..969863b 100644
--- a/src/main/kotlin/info/mking/k2zpl/command/BarCode.kt
+++ b/src/main/kotlin/info/mking/k2zpl/command/BarCode.kt
@@ -2,7 +2,6 @@ package info.mking.k2zpl.command
 
 import info.mking.k2zpl.builder.ZplBuilder
 import info.mking.k2zpl.builder.command
-import info.mking.k2zpl.builder.fieldData
 import info.mking.k2zpl.builder.toZplYesNo
 import info.mking.k2zpl.command.options.ZplBarcodeType
 import info.mking.k2zpl.command.options.ZplFieldOrientation
diff --git a/src/main/kotlin/info/mking/k2zpl/command/FieldData.kt b/src/main/kotlin/info/mking/k2zpl/command/FieldData.kt
index 0f94ac0..7f8c38e 100644
--- a/src/main/kotlin/info/mking/k2zpl/command/FieldData.kt
+++ b/src/main/kotlin/info/mking/k2zpl/command/FieldData.kt
@@ -1,6 +1,17 @@
 package info.mking.k2zpl.command
 
+import info.mking.k2zpl.builder.ZplBuilder
+import info.mking.k2zpl.builder.command
+
 internal data class FieldData(val data: String) : ZplCommand {
     override val command: CharSequence = "^FD"
     override val parameters: LinkedHashMap<CharSequence, Any?> = linkedMapOf("d" to data)
+}
+
+/**
+ * Adds field data.
+ * @param data The data to be added to the field.
+ */
+fun ZplBuilder.fieldData(data: String) {
+    command(FieldData(data))
 }
\ No newline at end of file
diff --git a/src/test/kotlin/info/mking/k2zpl/command/FieldDataTest.kt b/src/test/kotlin/info/mking/k2zpl/command/FieldDataTest.kt
new file mode 100644
index 0000000..1d7304b
--- /dev/null
+++ b/src/test/kotlin/info/mking/k2zpl/command/FieldDataTest.kt
@@ -0,0 +1,27 @@
+package info.mking.k2zpl.command
+
+import info.mking.k2zpl.k2zpl
+import info.mking.k2zpl.testBuildString
+import io.kotest.core.spec.IsolationMode
+import io.kotest.core.spec.style.DescribeSpec
+import io.kotest.matchers.shouldBe
+
+class FieldDataTest : DescribeSpec({
+    isolationMode = IsolationMode.InstancePerLeaf
+
+    val fieldData = FieldData("some-data")
+
+    describe("FieldData") {
+        it("outputs correct command") {
+            fieldData.testBuildString() shouldBe "^FDsome-data"
+        }
+    }
+    describe("fieldData extension function") {
+        it("outputs correct command") {
+            val result = k2zpl {
+                fieldData("some-other-data")
+            }
+            result shouldBe "^FDsome-other-data\n"
+        }
+    }
+})
\ No newline at end of file