diff --git a/adafruit_waveform/sine.py b/adafruit_waveform/sine.py
index 5fc0cac..ace2455 100644
--- a/adafruit_waveform/sine.py
+++ b/adafruit_waveform/sine.py
@@ -19,7 +19,7 @@
 __repo__ = "https://github.com/adafruit/Adafruit_CircuitPython_Waveform.git"
 
 
-def sine_wave(sample_frequency, pitch):
+def sine_wave(sample_frequency: float, pitch: float):
     """Generate a single sine wav cycle at the given sampling frequency and pitch."""
     length = int(sample_frequency / pitch)
     b = array.array("H", [0] * length)
diff --git a/adafruit_waveform/square.py b/adafruit_waveform/square.py
index a2c4ba5..d4fdf4d 100644
--- a/adafruit_waveform/square.py
+++ b/adafruit_waveform/square.py
@@ -18,7 +18,7 @@
 __repo__ = "https://github.com/adafruit/Adafruit_CircuitPython_Waveform.git"
 
 
-def square_wave(sample_length=2):
+def square_wave(sample_length: int = 2):
     """Generate a single square wave of sample_length size"""
     square = array.array("H", [0] * sample_length)
     for i in range(sample_length // 2):