diff --git a/src/UnitConverter/Unit/Length/LengthUnit.php b/src/UnitConverter/Unit/Length/LengthUnit.php
index b3297820..7dc24f9a 100644
--- a/src/UnitConverter/Unit/Length/LengthUnit.php
+++ b/src/UnitConverter/Unit/Length/LengthUnit.php
@@ -26,7 +26,7 @@
  * @since 1.0.0
  * @author Jordan Brauer <jbrauer.inc@gmail.com>
  */
-class LengthUnit extends AbstractUnit
+abstract class LengthUnit extends AbstractUnit
 {
   protected $unitOf = Measure::LENGTH;