diff --git a/notebook_nueva/battery_holder.py b/notebook_nueva/battery_holder.py
index 0ab21ef..57f6beb 100644
--- a/notebook_nueva/battery_holder.py
+++ b/notebook_nueva/battery_holder.py
@@ -124,43 +124,45 @@ def add(
     shell_t
 ):
 
-    # Vents
-    for vent in vents:
-        model = punch_hole2(
-            model=model,
-            face=bottom_face,
-            w=width,
-            h=height,
-            x_offset=offset_x + vent["x"],
-            y_offset=shell_t + offset_y + vent["y"],
-            hole=vent,
-            depth=shell_t,
-        )
+    if bottom_face:
+        # Vents
+        for vent in vents:
+            model = punch_hole2(
+                model=model,
+                face=bottom_face,
+                w=width,
+                h=height,
+                x_offset=offset_x + vent["x"],
+                y_offset=shell_t + offset_y + vent["y"],
+                hole=vent,
+                depth=shell_t,
+            )
 
-    # Battery holder stands and pogo pin holder
-    for element in elements:
-        model = extrude_shape(
-            model=model,
-            face=bottom_face,
-            w=width,
-            h=height,
-            x_offset=offset_x + element["x"],
-            y_offset=shell_t + offset_y + element["y"],
-            shape=element["shape"],
-            height=-(element["height"] + shell_t),
-        )
+        # Battery holder stands and pogo pin holder
+        for element in elements:
+            model = extrude_shape(
+                model=model,
+                face=bottom_face,
+                w=width,
+                h=height,
+                x_offset=offset_x + element["x"],
+                y_offset=shell_t + offset_y + element["y"],
+                shape=element["shape"],
+                height=-(element["height"] + shell_t),
+            )
 
-    # Holes
-    for hole in holes:
-        model = punch_hole2(
-            model=model,
-            face=back_face,
-            w=width,
-            h=thickness,
-            x_offset=width - offset_x,
-            y_offset=shell_t,
-            hole=hole,
-            depth=shell_t,
-        )
+    if back_face:
+        # Holes
+        for hole in holes:
+            model = punch_hole2(
+                model=model,
+                face=back_face,
+                w=width,
+                h=thickness,
+                x_offset=width - offset_x,
+                y_offset=shell_t,
+                hole=hole,
+                depth=shell_t,
+            )
 
     return model
diff --git a/notebook_nueva/modelo.py b/notebook_nueva/modelo.py
index e6b7626..6e18034 100644
--- a/notebook_nueva/modelo.py
+++ b/notebook_nueva/modelo.py
@@ -200,7 +200,7 @@ def model():
         offset_x=cpu_offset_x,
         offset_y=cpu_offset_y,
         bottom_face="<Z",
-        back_face=None,
+        back_face=None,  # Not exposing the holes
         shell_t=shell_t,
     )
 
diff --git a/notebook_nueva/utils.py b/notebook_nueva/utils.py
index 205b1b6..7335894 100644
--- a/notebook_nueva/utils.py
+++ b/notebook_nueva/utils.py
@@ -33,4 +33,4 @@ def punch_hole2(*, model, face, w, h, x_offset, y_offset, hole, depth):
         .center(-w / 2 + x_offset + hole["x"], -h / 2 + y_offset + hole["y"])
         .placeSketch(hole["shape"])
         .cutBlind(-depth)
-    )
+    )
\ No newline at end of file
diff --git a/notebook_nueva/zero_holder.py b/notebook_nueva/zero_holder.py
index 2b97b04..8f9ec5d 100644
--- a/notebook_nueva/zero_holder.py
+++ b/notebook_nueva/zero_holder.py
@@ -60,7 +60,14 @@ vents = [
     }
 ]
 
-holes = []  # TODO
+holes = [
+    # One hole for everything TODO: improve
+    {
+        "x": -width / 2,
+        "y": 1 + pillar_height,
+        "shape": cq.Sketch().trapezoid(50, 6, 90, mode="a").vertices().fillet(1),
+    }
+]
 
 
 def add(
@@ -76,43 +83,45 @@ def add(
     shell_t
 ):
 
-    # Vents
-    for vent in vents:
-        model = punch_hole2(
-            model=model,
-            face=bottom_face,
-            w=width,
-            h=height,
-            x_offset=offset_x + vent["x"],
-            y_offset=shell_t + offset_y + vent["y"],
-            hole=vent,
-            depth=shell_t,
-        )
+    if bottom_face:
+        # Vents
+        for vent in vents:
+            model = punch_hole2(
+                model=model,
+                face=bottom_face,
+                w=width,
+                h=height,
+                x_offset=offset_x + vent["x"],
+                y_offset=shell_t + offset_y + vent["y"],
+                hole=vent,
+                depth=shell_t,
+            )
 
-    # CPU holder extrusions
-    for element in elements:
-        model = extrude_shape(
-            model=model,
-            face=bottom_face,
-            w=width,
-            h=height,
-            x_offset=offset_x + element["x"],
-            y_offset=shell_t + offset_y + element["y"],
-            shape=element["shape"],
-            height=-(element["height"] + shell_t),
-        )
+        # CPU holder extrusions
+        for element in elements:
+            model = extrude_shape(
+                model=model,
+                face=bottom_face,
+                w=width,
+                h=height,
+                x_offset=offset_x + element["x"],
+                y_offset=shell_t + offset_y + element["y"],
+                shape=element["shape"],
+                height=-(element["height"] + shell_t),
+            )
 
     # Holes
-    for hole in holes:
-        model = punch_hole2(
-            model=model,
-            face=back_face,
-            w=width,
-            h=thickness,
-            x_offset=width - offset_x,
-            y_offset=shell_t,
-            hole=hole,
-            depth=shell_t,
-        )
+    if back_face:
+        for hole in holes:
+            model = punch_hole2(
+                model=model,
+                face=back_face,
+                w=width,
+                h=thickness,
+                x_offset=width - offset_x,
+                y_offset=shell_t,
+                hole=hole,
+                depth=shell_t,
+            )
 
     return model