diff --git a/std/assembly/vector.ts b/std/assembly/vector.ts
index 6aceaf46..c7f1afa3 100644
--- a/std/assembly/vector.ts
+++ b/std/assembly/vector.ts
@@ -1,3 +1,4 @@
 /** Vector abstraction. */
-@sealed export class V128 {
+@sealed @unmanaged
+export abstract class V128 {
 }