diff --git a/src/Transaction/PSBT/PSBT.php b/src/Transaction/PSBT/PSBT.php
index 8c0d659eb..cd0adcf8b 100644
--- a/src/Transaction/PSBT/PSBT.php
+++ b/src/Transaction/PSBT/PSBT.php
@@ -167,8 +167,9 @@ public function getTransaction(): TransactionInterface
     {
         return $this->tx;
     }
+
     /**
-     * @return string[]
+     * @return BufferInterface[]
      */
     public function getUnknowns(): array
     {
diff --git a/src/Transaction/PSBT/PSBTInput.php b/src/Transaction/PSBT/PSBTInput.php
index f953f1f04..bfbf2c882 100644
--- a/src/Transaction/PSBT/PSBTInput.php
+++ b/src/Transaction/PSBT/PSBTInput.php
@@ -373,6 +373,9 @@ public function getFinalizedScriptWitness(): ScriptWitnessInterface
         return $this->finalScriptWitness;
     }
 
+    /**
+     * @return BufferInterface[]
+     */
     public function getUnknownFields(): array
     {
         return $this->unknown;
diff --git a/src/Transaction/PSBT/PSBTOutput.php b/src/Transaction/PSBT/PSBTOutput.php
index 2ad5166ee..bf70675b3 100644
--- a/src/Transaction/PSBT/PSBTOutput.php
+++ b/src/Transaction/PSBT/PSBTOutput.php
@@ -161,7 +161,7 @@ public function getBip32Derivations(): array
     }
 
     /**
-     * @return string[]
+     * @return BufferInterface[]
      */
     public function getUnknownFields(): array
     {