diff --git a/columbus/env.py b/columbus/env.py
index 1814915..acc8651 100644
--- a/columbus/env.py
+++ b/columbus/env.py
@@ -855,6 +855,8 @@ class ColumbusConfigDefined(ColumbusEnv):
         if type(s) in [int, float]:
             return s
         if s.replace('.', '', 1).isdigit():
+            if target == 'px':
+                return int(s)
             return float(s)
         num, unit = s[:-2], s[-2:]
         num = float(num)
@@ -876,7 +878,7 @@ class ColumbusConfigDefined(ColumbusEnv):
         if target == 'em':
             return em
         elif target == 'px':
-            return em * ({'x': self.width, 'y': self.height}[axis])
+            return int(em * ({'x': self.width, 'y': self.height}[axis]))
 
     def setup(self):
         self.agent.pos = self.start_pos
diff --git a/configs/Example_Units.yaml b/configs/Example_Units.yaml
index 14c005e..4e621a4 100644
--- a/configs/Example_Units.yaml
+++ b/configs/Example_Units.yaml
@@ -63,6 +63,11 @@ params:
           width: 25ry
           height: 25rx
           pos: [0.75em, 60px]
+        - type: RectBarrier
+          num: 1
+          width: 2ct
+          height: 3ct
+          pos: [0.75em, 90px]
         - type: OnceReward
           reward: 100
           radius: 3ct