diff --git a/assemblyai/extras.py b/assemblyai/extras.py
index 7e844b3..5086b70 100644
--- a/assemblyai/extras.py
+++ b/assemblyai/extras.py
@@ -1,5 +1,5 @@
 import time
-from typing import BinaryIO, Generator
+from typing import BinaryIO, Generator, Optional
 from warnings import warn
 
 from . import api
@@ -22,17 +22,13 @@ def __init__(
 
 
 class MicrophoneStream:
-    def __init__(
-        self,
-        sample_rate: int = 44_100,
-    ):
+    def __init__(self, sample_rate: int = 44_100, device_index: Optional[int] = None):
         """
         Creates a stream of audio from the microphone.
 
         Args:
-            chunk_size: The size of each chunk of audio to read from the microphone.
-            channels: The number of channels to record audio from.
             sample_rate: The sample rate to record audio at.
+            device_index: The index of the input device to use. If None, uses the default device.
         """
         try:
             import pyaudio
@@ -49,6 +45,7 @@ def __init__(
             rate=sample_rate,
             input=True,
             frames_per_buffer=self._chunk_size,
+            input_device_index=device_index,
         )
 
         self._open = True