diff --git a/README.md b/README.md
index 2310575..5842e3d 100644
--- a/README.md
+++ b/README.md
@@ -2,8 +2,57 @@
 
 # Clean Code Rules
 
-- `no-number`: Avoid using numbers at the end of variable or function names.
-  - extensions: `.ts`, `.js` (default)
+# `no-number`
+
+Avoid using numbers at the end of variable or function names.
+
+## Rule Details
+
+Examples of **incorrect** code for this rule:
+
+```js
+const foo1 = 1;
+const bar2 = 2;
+
+function baz3() {
+  return 3;
+}
+```
+
+Examples of **correct** code for this rule:
+
+```js
+
+const foo = 1;
+const bar = 2;
+
+function baz() {
+  return 3;
+}
+```
+
+### Options
+
+You can pass an `allow` option to specify a list of variable or function names that are allowed to have numbers at the end. 
+By default, the rule allows `s3` and `v4` as they are common in the JavaScript world. (e.g. `s3` for AWS S3, `v4` for UUID v4)
+
+```json
+{
+  "clean-code/no-number": ["error", {
+    "allow": ["s3", "v4"]
+  }]
+}
+```
+
+You can pass an `extensions` option to specify a list of file extensions that will be checked. By default, the rule checks `.js`, `.jsx`, `.ts`, and `.tsx` files.
+
+```json
+{
+  "clean-code/no-number": ["error", {
+    "extensions": [".js", ".jsx", ".ts", ".tsx"]
+  }]
+}
+```
 
 # Installation
 
diff --git a/package.json b/package.json
index 9a0daf8..6184b10 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@kougen/eslint-plugin-clean-code",
-  "version": "1.1.6",
+  "version": "1.2.0",
   "description": "Custom eslint rules for clean code.",
   "main": "dist/index.js",
   "readme": "README.md",
diff --git a/src/rules/no-variable-with-number-at-end.test.ts b/src/rules/no-variable-with-number-at-end.test.ts
index 8b9e680..d11602d 100644
--- a/src/rules/no-variable-with-number-at-end.test.ts
+++ b/src/rules/no-variable-with-number-at-end.test.ts
@@ -29,16 +29,61 @@ ruleTester.run(
   noVariableWithNumberAtEnd,
   {
     valid: [
-      {code: "const foo = 'bar';", filename: "file.ts", options: [{extensions: [".ts"]}]},
-      {code: "const foo123 = 'bar';", filename: "file.js", options: [{extensions: [".ts"]}]},
+      {
+        code: "const foo = 'bar';",
+        filename: "file.ts",
+        options: [{extensions: [".ts"], allow: ["s3", "v4"]}]
+      },
+      {
+        code: "const foo123 = 'bar';",
+        filename: "file.js",
+        options: [{extensions: [".ts"], allow: ["s3", "v4"]}]
+      },
+    ],
+    invalid: [
+      {
+        code: "const foo2 = 'bar';",
+        filename: "file.ts",
+        options: [{extensions: [".ts"], allow: ["s3", "v4"]}],
+        errors: [{messageId: "noNumberEnding"}],
+      }
+    ],
+  }
+);
+
+ruleTester.run(
+  "no-number (custom allow)",
+  noVariableWithNumberAtEnd,
+  {
+    valid: [
+      {
+        code: "const foo = 'bar';",
+        filename: "file.ts",
+        options: [{extensions: [".ts", ".js"], allow: ["s3", "v4"]}]
+      },
+      {
+        code: "const foo123 = 'bar';",
+        filename: "file.ts",
+        options: [{extensions: [".ts", ".js"], allow: ["foo123"]}]
+      },
+      {
+        code: "const s3 = 'bar';",
+        filename: "file.ts",
+        options: [{extensions: [".ts", ".js"], allow: ["s3", "v4"]}]
+      },
+      {
+        code: "const v4 = 'bar';",
+        filename: "file.ts",
+        options: [{extensions: [".ts", ".js"], allow: ["s3", "v4"]}]
+      },
     ],
     invalid: [
       {
         code: "const foo2 = 'bar';",
         filename: "file.ts",
-        options: [{extensions: [".ts"]}],
+        options: [{extensions: [".ts", ".js"], allow: ["s3", "v4"]}],
         errors: [{messageId: "noNumberEnding"}],
       }
     ],
   }
-);
\ No newline at end of file
+)
\ No newline at end of file
diff --git a/src/rules/no-variable-with-number-at-end.ts b/src/rules/no-variable-with-number-at-end.ts
index 3f0e243..d2c01ff 100644
--- a/src/rules/no-variable-with-number-at-end.ts
+++ b/src/rules/no-variable-with-number-at-end.ts
@@ -28,14 +28,20 @@ export default createRule({
           extensions: {
             type: "array",
             items: {type: "string"},
+            default: [".ts", ".js"],
+          },
+          allow: {
+            type: "array",
+            items: {type: "string"},
+            default: ["s3", "v4"],
           }
         },
         additionalProperties: false
-      }
+      },
     ],
   },
-  defaultOptions: [{extensions: [".ts", ".js"]}],
-  create(context, [{extensions}]) {
+  defaultOptions: [{extensions: [".ts", ".js"], allow: ["s3", "v4"]}],
+  create(context, [{extensions, allow}]) {
     const filename = context.filename;
     const ext = path.extname(filename);
 
@@ -45,7 +51,10 @@ export default createRule({
 
     return {
       Identifier(node) {
-        const variableName = node.name;
+        const variableName = node.name.toLowerCase();
+        if (allow.includes(variableName)) {
+          return;
+        }
         if (/\d$/.test(variableName)) {
           context.report({
             node,