diff --git a/README.md b/README.md
index 22eca20..54c644d 100644
--- a/README.md
+++ b/README.md
@@ -75,6 +75,16 @@ $rlp = new RLP;
 $encoded = $rlp->encode(['web3p', 'ethereum', 'solidity']);
 ```
 
+* Encode ethereum address
+
+There's an ability to force type of specific encoded item. For ethereum addresses, leading zeros can't be removed as these are specified as 20 byte array (not a string). To properly encode it you can pass it as hex_fixed.
+```
+use Web3p\RLP\RLP;
+
+$rlp = new RLP;
+$encoded = $rlp->encode(['web3p', '0x4f15a948f2e2a13731c9aa3cef52cdf8d3e6a120', 'test', '0x4f15a948f2e2a13731c9aa3cef52cdf8d3e6a120'], [1=>'hex_fixed', 3=>'hex_fixed']);
+```
+
 #### decode
 
 Returns array recursive length prefix decoding of given data.
diff --git a/src/RLP.php b/src/RLP.php
index 055090a..c49fb10 100644
--- a/src/RLP.php
+++ b/src/RLP.php
@@ -64,19 +64,20 @@ class RLP
      * Return RLP encoded of the given inputs.
      *
      * @param mixed $inputs mixed type of data you want to RLP encode
+	 * @param mixed $types mixed type of data you want to encode, if there's no $types[X] for corresponding $inputs[X] - will be autodetected
      * @return string RLP encoded hex string of inputs
      */
-    public function encode($inputs)
+    public function encode($inputs, $types = false)
     {
         $output = '';
         if (is_array($inputs)) {
-            foreach ($inputs as $input) {
-                $output .= $this->encode($input);
+            foreach ($inputs as $k=>$input) {
+                $output .= $this->encode($input, $types[$k] ?? false);
             }
             $length = mb_strlen($output) / 2;
             return $this->encodeLength($length, 192) . $output;
         }
-        $input = $this->encodeInput($inputs);
+        $input = $this->encodeInput($inputs, $types);
         $length = mb_strlen($input) / 2;
 
         // first byte < 0x80
@@ -247,20 +248,24 @@ protected function padToEven(string $input)
      * Main encode function to transform data to hex encoded string.
      *
      * @param mixed $input data
+	 * @param string type data type to be encoded for not-numeric type
      * @return string hex encoded string
      */
-    protected function encodeInput($input)
-    {
-        if (is_string($input)) {
-            if (strpos($input, '0x') === 0) {
-                return Str::encode($input, 'hex');
-            }
-            return Str::encode($input);
-        } elseif (is_numeric($input)) {
-            return Numeric::encode($input);
-        } elseif ($input === null) {
-            return '';
-        }
-        throw new InvalidArgumentException('The input type didn\'t support.');
-    }
+	protected function encodeInput($input, $type = false)
+	{
+		if (is_string($input)) {
+			if ($type !== false) {
+				return Str::encode($input, $type);
+			}
+			if (strpos($input, '0x') === 0) {
+				return Str::encode($input, 'hex');
+			}
+			return Str::encode($input);
+		} elseif (is_numeric($input)) {
+			return Numeric::encode($input);
+		} elseif ($input === null) {
+			return '';
+		}
+		throw new InvalidArgumentException('The input type didn\'t support.');
+	}
 }
diff --git a/src/Types/Str.php b/src/Types/Str.php
index 7cf210a..16f5e00 100644
--- a/src/Types/Str.php
+++ b/src/Types/Str.php
@@ -34,7 +34,15 @@ static function encode(string $input, string $encoding='utf8')
     {
         $output = '';
         switch ($encoding) {
-            case 'hex':
+			// fixed length hex
+			case 'hex_fixed':
+				if (strpos($input, '0x') === 0) {
+					$input = str_replace('0x', '', $input);
+				}
+				$output = $input;
+				break;
+			
+			case 'hex':
             if (strpos($input, '0x') === 0) {
                 $input = str_replace('0x', '', $input);
             }