diff --git a/src/Message/AIMAuthorizeRequest.php b/src/Message/AIMAuthorizeRequest.php
index 79ba07a7..8489f6f3 100644
--- a/src/Message/AIMAuthorizeRequest.php
+++ b/src/Message/AIMAuthorizeRequest.php
@@ -10,6 +10,21 @@
  */
 class AIMAuthorizeRequest extends AIMAbstractRequest
 {
+    const MARKET_TYPE_ECOMMERCE  = '0';
+    const MARKET_TYPE_MOTO       = '1';
+    const MARKET_TYPE_RETAIL     = '2';
+
+    const DEVICE_TYPE_UNKNOWN = '1';
+    const DEVICE_TYPE_UNATTENDED_TERMINAL = '2';
+    const DEVICE_TYPE_SELF_SERVICE_TERMINAL = '3';
+    const DEVICE_TYPE_ELECTRONIC_CASH_REGISTER = '4';
+    const DEVICE_TYPE_PC_BASED_TERMINAL = '5';
+    const DEVICE_TYPE_AIRPAY = '6';
+    const DEVICE_TYPE_WIRELESS_POS = '7';
+    const DEVICE_TYPE_WEBSITE = '8';
+    const DEVICE_TYPE_DIAL_TERMINAL = '9';
+    const DEVICE_TYPE_VIRTUAL_TERMINAL = '10';
+
     protected $action = 'authOnlyTransaction';
 
     public function getData()
@@ -71,14 +86,29 @@ protected function addRetail(\SimpleXMLElement $data)
         }
 
         if (isset($deviceType) && !isset($marketType)) {
-            $marketType = "2";
+            $marketType = static::MARKET_TYPE_RETAIL;
         }
 
-        if (!in_array($deviceType, [ "1", "2", "3", "4", "5", "6", "7", "8", "9", "10" ])) {
+        if (!in_array($deviceType, [
+            static::DEVICE_TYPE_UNKNOWN,
+            static::DEVICE_TYPE_UNATTENDED_TERMINAL,
+            static::DEVICE_TYPE_SELF_SERVICE_TERMINAL,
+            static::DEVICE_TYPE_ELECTRONIC_CASH_REGISTER,
+            static::DEVICE_TYPE_PC_BASED_TERMINAL,
+            static::DEVICE_TYPE_AIRPAY,
+            static::DEVICE_TYPE_WIRELESS_POS,
+            static::DEVICE_TYPE_WEBSITE,
+            static::DEVICE_TYPE_DIAL_TERMINAL,
+            static::DEVICE_TYPE_VIRTUAL_TERMINAL,
+        ])) {
             throw new InvalidRequestException("deviceType `{$deviceType}` is invalid");
         }
 
-        if (!in_array($marketType, [ "0", "1", "2" ])) {
+        if (!in_array($marketType, [
+            static::MARKET_TYPE_ECOMMERCE,
+            static::MARKET_TYPE_MOTO,
+            static::MARKET_TYPE_RETAIL,
+        ])) {
             throw new InvalidRequestException("marketType `{$marketType}` is invalid");
         }