diff --git a/src/snowflake/src/Meta.php b/src/snowflake/src/Meta.php
index 22ed43840..cc582fa6b 100644
--- a/src/snowflake/src/Meta.php
+++ b/src/snowflake/src/Meta.php
@@ -72,32 +72,28 @@ class Meta
         $this->sequence = $sequence;
     }
 
-    /**
-     * @param int $timestamp
-     * @return Meta
-     */
     public function setTimestamp(int $timestamp): self
     {
         $this->timestamp = $timestamp;
         return $this;
     }
 
-    protected function maxMachineId()
+    protected function maxMachineId(): int
     {
         return -1 ^ (-1 << self::MACHINE_ID_BITS);
     }
 
-    protected function maxDataCenterId()
+    protected function maxDataCenterId(): int
     {
         return -1 ^ (-1 << self::DATA_CENTER_ID_BITS);
     }
 
-    protected function maxBusinessId()
+    protected function maxBusinessId(): int
     {
         return -1 ^ (-1 << self::BUSINESS_ID_BITS);
     }
 
-    protected function maxSequence()
+    protected function maxSequence(): int
     {
         return -1 ^ (-1 << self::SEQUENCE_BITS);
     }
diff --git a/src/snowflake/src/Snowflake.php b/src/snowflake/src/Snowflake.php
index 4f189de6c..b96121788 100644
--- a/src/snowflake/src/Snowflake.php
+++ b/src/snowflake/src/Snowflake.php
@@ -65,22 +65,22 @@ class Snowflake implements IdGeneratorInterface
         ))->setTimestamp($timestamp + $this->beginSecond);
     }
 
-    protected function getTimestampShift()
+    protected function getTimestampShift(): int
     {
         return Meta::SEQUENCE_BITS + Meta::MACHINE_ID_BITS + Meta::DATA_CENTER_ID_BITS + Meta::BUSINESS_ID_BITS;
     }
 
-    protected function getBusinessIdShift()
+    protected function getBusinessIdShift(): int
     {
         return Meta::SEQUENCE_BITS + Meta::MACHINE_ID_BITS + Meta::DATA_CENTER_ID_BITS;
     }
 
-    protected function getDataCenterShift()
+    protected function getDataCenterShift(): int
     {
         return Meta::SEQUENCE_BITS + Meta::MACHINE_ID_BITS;
     }
 
-    protected function getMachineIdShift()
+    protected function getMachineIdShift(): int
     {
         return Meta::SEQUENCE_BITS;
     }