diff --git a/wpilibj/src/main/java/edu/wpi/first/wpilibj/simulation/CallbackStore.java b/wpilibj/src/main/java/edu/wpi/first/wpilibj/simulation/CallbackStore.java
index 69daa87ff8..b9bc746a23 100644
--- a/wpilibj/src/main/java/edu/wpi/first/wpilibj/simulation/CallbackStore.java
+++ b/wpilibj/src/main/java/edu/wpi/first/wpilibj/simulation/CallbackStore.java
@@ -21,6 +21,20 @@ public class CallbackStore implements AutoCloseable {
     void cancel(int uid);
   }
 
+  /**
+   * Constructs an empty CallbackStore. This constructor is to allow 3rd party sim providers (eg
+   * vendors) to subclass this class (without needing provide dummy constructing parameters) so that
+   * the register methods of their sim classes can return CallbackStores like the builtin sims.
+   * <b>Note: It should not be called by teams that are just using sims!</b>
+   */
+  protected CallbackStore() {
+    this.m_cancelType = -1;
+    this.m_index = -1;
+    this.m_uid = -1;
+    this.m_cancelCallback = null;
+    this.m_cancelCallbackChannel = null;
+  }
+
   /**
    * <b>Note: This constructor is for simulation classes only. It should not be called by teams!</b>
    *