diff --git a/adafruit_ads1x15/ads1x15.py b/adafruit_ads1x15/ads1x15.py
index 573b9e7..5cd7cd0 100644
--- a/adafruit_ads1x15/ads1x15.py
+++ b/adafruit_ads1x15/ads1x15.py
@@ -127,7 +127,7 @@ class ADS1x15:
 
     def __init__(
         self,
-        i2c: I2C,
+        i2c: "I2C",
         gain: float = 1,
         data_rate: Optional[int] = None,
         mode: int = Mode.SINGLE,