diff --git a/packages/util/src/FlexibleBuffer.ts b/packages/util/src/FlexibleBuffer.ts
index 1e5f3d1f8..9c47ed0d0 100644
--- a/packages/util/src/FlexibleBuffer.ts
+++ b/packages/util/src/FlexibleBuffer.ts
@@ -13,11 +13,17 @@ interface IFlexibleBuffer {
 }
 
 export abstract class FlexibleBuffer implements IFlexibleBuffer {
-  static flexible() {
+  static auto(size?: number | null): FlexibleBuffer {
+    return typeof size === "number"
+      ? new BufferFlexibleBuffer(size)
+      : new ArrayFlexibleBuffer();
+  }
+
+  static flexible(): FlexibleBuffer {
     return new ArrayFlexibleBuffer();
   }
 
-  static fixed(size: number) {
+  static fixed(size: number): FlexibleBuffer {
     return new BufferFlexibleBuffer(size);
   }
 
@@ -29,15 +35,15 @@ export abstract class FlexibleBuffer implements IFlexibleBuffer {
   abstract toJSON(): IBufferJson
 }
 
-export class BufferFlexibleBuffer extends FlexibleBuffer {
-  private readonly _buffer: Buffer;
-  private _index: number = 0;
-
+class BufferFlexibleBuffer extends FlexibleBuffer {
   constructor(size: number) {
     super();
     this._buffer = Buffer.alloc(size);
   }
 
+  private readonly _buffer: Buffer;
+  private _index: number = 0;
+
   get length(): number {
     return this._index;
   }
@@ -66,7 +72,7 @@ export class BufferFlexibleBuffer extends FlexibleBuffer {
   }
 }
 
-export class ArrayFlexibleBuffer extends FlexibleBuffer {
+class ArrayFlexibleBuffer extends FlexibleBuffer {
   private readonly _buffer: any[] = [];
   private _length = 0;
 
diff --git a/packages/util/src/index.ts b/packages/util/src/index.ts
index 4d9ad61a5..be73f9540 100644
--- a/packages/util/src/index.ts
+++ b/packages/util/src/index.ts
@@ -3,11 +3,10 @@ import "source-map-support/register";
 export * from "./BitField";
 export * from "./config";
 export * from "./FileResolver";
+export * from "./FlexibleBuffer";
 export * from "./glob";
 export * from "./JSON";
 export * from "./ModPermissionsBF";
 export * from "./utils";
 
-export { FlexibleBuffer } from "./FlexibleBuffer";
-
 export const version: string = "__PACKAGE_VERSION__";
diff --git a/packages/util/src/test/FlexibleBuffer.test.ts b/packages/util/src/test/FlexibleBuffer.test.ts
index 81364880e..002bd6a0c 100644
--- a/packages/util/src/test/FlexibleBuffer.test.ts
+++ b/packages/util/src/test/FlexibleBuffer.test.ts
@@ -1,28 +1,22 @@
 import assert from "assert";
 import test, { suite } from "node:test";
-import { ArrayFlexibleBuffer, BufferFlexibleBuffer, FlexibleBuffer } from "../FlexibleBuffer";
+import { FlexibleBuffer } from "../FlexibleBuffer";
+
+const array = [1, 2, 3];
 
 suite("Array FlexibleBuffer", () => {
   const buffer = FlexibleBuffer.flexible();
 
-  test("Instance must be ArrayBased", () => {
-    assert(buffer instanceof ArrayFlexibleBuffer);
-  });
-
   test("Allow push oversized", () => {
-    buffer.push([1, 2, 3]);
-    assert(buffer.length === 3);
+    buffer.push(array);
+    assert.strictEqual(buffer.length, array.length);
   });
 });
 
 suite("Buffer FlexibleBuffer", () => {
-  const buffer = FlexibleBuffer.fixed(0);
-
-  test("Instance must be BufferBased", () => {
-    assert(buffer instanceof BufferFlexibleBuffer);
-  });
+  const buffer = FlexibleBuffer.fixed(1);
 
   test("Deny push oversized", () => {
-    assert.throws(() => buffer.push([0]));
+    assert.throws(() => buffer.push(array));
   });
 });