diff --git a/libs/angular-three-soba/materials/src/lib/mesh-distort-material/mesh-distort-material.ts b/libs/angular-three-soba/materials/src/lib/mesh-distort-material/mesh-distort-material.ts
index 841a292..500b9e0 100644
--- a/libs/angular-three-soba/materials/src/lib/mesh-distort-material/mesh-distort-material.ts
+++ b/libs/angular-three-soba/materials/src/lib/mesh-distort-material/mesh-distort-material.ts
@@ -1,6 +1,6 @@
 import { Component, CUSTOM_ELEMENTS_SCHEMA, inject, Input } from '@angular/core';
 import { injectBeforeRender, injectNgtRef, NgtArgs, NgtRxStore } from 'angular-three';
-import { NGTS_DISTORT_MATERIAL_SHADER } from 'angular-three-soba/shaders';
+import { MeshDistortMaterial, NGTS_DISTORT_MATERIAL_SHADER } from 'angular-three-soba/shaders';
 
 @Component({
     selector: 'ngts-mesh-distort-material',
@@ -24,7 +24,7 @@ export class NgtsMeshDistortMaterial extends NgtRxStore {
 
     readonly material = new this.MeshDistortMaterial();
 
-    @Input() materialRef = injectNgtRef<typeof this.MeshDistortMaterial>();
+    @Input() materialRef = injectNgtRef<InstanceType<MeshDistortMaterial>>();
 
     @Input() set time(time: number) {
         this.set({ time });
diff --git a/libs/angular-three-soba/materials/src/lib/mesh-refraction-material/mesh-refraction-material.ts b/libs/angular-three-soba/materials/src/lib/mesh-refraction-material/mesh-refraction-material.ts
index 5d40d8f..9e65603 100644
--- a/libs/angular-three-soba/materials/src/lib/mesh-refraction-material/mesh-refraction-material.ts
+++ b/libs/angular-three-soba/materials/src/lib/mesh-refraction-material/mesh-refraction-material.ts
@@ -36,7 +36,7 @@ const isCubeTexture = (def: THREE.CubeTexture | THREE.Texture): def is THREE.Cub
     schemas: [CUSTOM_ELEMENTS_SCHEMA],
 })
 export class NgtsMeshRefractionMaterial extends NgtRxStore implements OnInit {
-    @Input() materialRef = injectNgtRef<typeof MeshRefractionMaterial.prototype>();
+    @Input() materialRef = injectNgtRef<InstanceType<typeof MeshRefractionMaterial>>();
     /** Environment map */
     @Input() set envMap(envMap: THREE.CubeTexture | THREE.Texture) {
         this.set({ envMap });