diff --git a/README.md b/README.md
index 00c0c5f..59ca691 100644
--- a/README.md
+++ b/README.md
@@ -39,7 +39,7 @@ export default () => {
 | `height`         | number  |    ✓     | Individual number height                 |
 | `width`          | number  |    ✓     | Individual number width                  |
 | `color`          | string  |    ✓     | Number color                             |
-| `background`     | string  |    ✓     | Background color                         |
+| `background`     | string  |          | Background color                         |
 | `perspective`    | number  |          | Css 3D transition perspective            |
 | `nonNumberStyle` | string  |          | Css inline style for not number eg , : . |
 | `numberStyle`    | string  |          | Css inline style for number              |
diff --git a/src/flipNumber.js b/src/flipNumber.js
index 3359364..23f6d0f 100644
--- a/src/flipNumber.js
+++ b/src/flipNumber.js
@@ -18,7 +18,7 @@ type Props = {
   length: number,
   height: number,
   color: string,
-  background: string,
+  background?: string,
   width: number,
   perspective: number,
   duration: number,
diff --git a/src/flipNumbers.js b/src/flipNumbers.js
index 3278e2a..f66943d 100644
--- a/src/flipNumbers.js
+++ b/src/flipNumbers.js
@@ -8,7 +8,7 @@ type Props = {
   height: number,
   width: number,
   color: string,
-  background: string,
+  background?: string,
   perspective?: number,
   duration?: number,
   delay?: number,