diff --git a/FastRng/Double/Distributions/Exponential.cs b/FastRng/Double/Distributions/Exponential.cs
index c390e5d..27467e9 100644
--- a/FastRng/Double/Distributions/Exponential.cs
+++ b/FastRng/Double/Distributions/Exponential.cs
@@ -22,7 +22,7 @@ namespace FastRng.Double.Distributions
             }
         }
 
-        public async ValueTask<double> GetDistributedValue(CancellationToken token)
+        public async ValueTask<double> GetDistributedValue(CancellationToken token = default)
         {
             if (this.Random == null)
                 return System.Double.NaN;