diff --git a/src/nman.ts b/src/nman.ts
index c4aeb9d..5a28f57 100644
--- a/src/nman.ts
+++ b/src/nman.ts
@@ -9,10 +9,10 @@ async function exitHandler() {
 
 export class ShutdownTasks {
     static list: ShutdownTasks[][] = [];
-    task: () => Promise<any> | void;
+    task: () => Promise<void> | void;
     maxMillis: number;
     order: number;
-    constructor(task: () => Promise<any> | void, maxMillis: number, order: number) {
+    constructor(task: () => Promise<void> | void, maxMillis: number, order: number) {
         this.task = task;
         this.maxMillis = maxMillis;
         this.order = order;
@@ -25,7 +25,7 @@ export class ShutdownTasks {
     }
 }
 
-export const addShutdownTask = function (task: () => Promise<any> | void, maxMillis = 5000, order = 1) {
+export const addShutdownTask = function (task: () => Promise<void> | void, maxMillis = 5000, order = 1) {
     return new ShutdownTasks(task, maxMillis, order);
 };