diff --git a/clouddrift/ragged.py b/clouddrift/ragged.py
index 13a77148..b3b04c48 100644
--- a/clouddrift/ragged.py
+++ b/clouddrift/ragged.py
@@ -791,14 +791,9 @@ def _mask_var(
     """
     if isinstance(criterion, tuple):  # min/max defining range
         mask = np.logical_and(var >= criterion[0], var <= criterion[1])
-    elif isinstance(
-        criterion, (list, np.ndarray, xr.DataArray)
-    ):  # select multiple values
-        # Ensure we define the mask as boolean, otherwise it will inherit
-        # the dtype of the variable which may be a string, object, or other.
-        mask = xr.zeros_like(var, dtype=bool)
-        for v in criterion:
-            mask = np.logical_or(mask, var == v)
+    elif isinstance(criterion, (list, np.ndarray, xr.DataArray)):
+        # select multiple values
+        mask = np.isin(var, criterion)
     else:  # select one specific value
         mask = var == criterion
     return mask