diff --git a/js/common/model/Cone.js b/js/common/model/Cone.js
index a2f48e8a..21dd172c 100644
--- a/js/common/model/Cone.js
+++ b/js/common/model/Cone.js
@@ -12,6 +12,7 @@ import Vector2 from '../../../../dot/js/Vector2.js';
 import Vector3 from '../../../../dot/js/Vector3.js';
 import Shape from '../../../../kite/js/Shape.js';
 import merge from '../../../../phet-core/js/merge.js';
+import IOType from '../../../../tandem/js/types/IOType.js';
 import densityBuoyancyCommon from '../../densityBuoyancyCommon.js';
 import Mass from './Mass.js';
 
@@ -294,5 +295,12 @@ class Cone extends Mass {
   }
 }
 
+// @public {IOType}
+Cone.ConeIO = new IOType( 'ConeIO', {
+  valueType: Cone,
+  supertype: Mass.MassIO,
+  documentation: 'Represents an up/down cone'
+} );
+
 densityBuoyancyCommon.register( 'Cone', Cone );
 export default Cone;
\ No newline at end of file
diff --git a/js/common/model/Ellipsoid.js b/js/common/model/Ellipsoid.js
index dc708f5b..3658575c 100644
--- a/js/common/model/Ellipsoid.js
+++ b/js/common/model/Ellipsoid.js
@@ -13,6 +13,7 @@ import Vector2 from '../../../../dot/js/Vector2.js';
 import Vector3 from '../../../../dot/js/Vector3.js';
 import Shape from '../../../../kite/js/Shape.js';
 import merge from '../../../../phet-core/js/merge.js';
+import IOType from '../../../../tandem/js/types/IOType.js';
 import densityBuoyancyCommon from '../../densityBuoyancyCommon.js';
 import Mass from './Mass.js';
 
@@ -247,5 +248,12 @@ class Ellipsoid extends Mass {
   }
 }
 
+// @public {IOType}
+Ellipsoid.EllipsoidIO = new IOType( 'EllipsoidIO', {
+  valueType: Ellipsoid,
+  supertype: Mass.MassIO,
+  documentation: 'Represents an ellipsoid'
+} );
+
 densityBuoyancyCommon.register( 'Ellipsoid', Ellipsoid );
 export default Ellipsoid;
\ No newline at end of file
diff --git a/js/common/model/HorizontalCylinder.js b/js/common/model/HorizontalCylinder.js
index a8db0196..93efe995 100644
--- a/js/common/model/HorizontalCylinder.js
+++ b/js/common/model/HorizontalCylinder.js
@@ -11,6 +11,7 @@ import Utils from '../../../../dot/js/Utils.js';
 import Vector3 from '../../../../dot/js/Vector3.js';
 import Shape from '../../../../kite/js/Shape.js';
 import merge from '../../../../phet-core/js/merge.js';
+import IOType from '../../../../tandem/js/types/IOType.js';
 import densityBuoyancyCommon from '../../densityBuoyancyCommon.js';
 import Mass from './Mass.js';
 
@@ -255,5 +256,12 @@ class HorizontalCylinder extends Mass {
   }
 }
 
+// @public {IOType}
+HorizontalCylinder.HorizontalCylinderIO = new IOType( 'HorizontalCylinderIO', {
+  valueType: HorizontalCylinder,
+  supertype: Mass.MassIO,
+  documentation: 'Represents a cylinder laying on its side'
+} );
+
 densityBuoyancyCommon.register( 'HorizontalCylinder', HorizontalCylinder );
 export default HorizontalCylinder;
\ No newline at end of file
diff --git a/js/common/model/Scale.js b/js/common/model/Scale.js
index 4c08a126..895d1bcb 100644
--- a/js/common/model/Scale.js
+++ b/js/common/model/Scale.js
@@ -11,6 +11,7 @@ import Vector3 from '../../../../dot/js/Vector3.js';
 import Shape from '../../../../kite/js/Shape.js';
 import Enumeration from '../../../../phet-core/js/Enumeration.js';
 import merge from '../../../../phet-core/js/merge.js';
+import IOType from '../../../../tandem/js/types/IOType.js';
 import densityBuoyancyCommon from '../../densityBuoyancyCommon.js';
 import Cuboid from './Cuboid.js';
 import InterpolatedProperty from './InterpolatedProperty.js';
@@ -198,5 +199,12 @@ Scale.SCALE_FRONT_OFFSET = SCALE_FRONT_OFFSET;
 // @public {Enumeration}
 Scale.DisplayType = DisplayType;
 
+// @public {IOType}
+Scale.ScaleIO = new IOType( 'ScaleIO', {
+  valueType: Scale,
+  supertype: Mass.MassIO,
+  documentation: 'Represents scale used for measuring mass/weight'
+} );
+
 densityBuoyancyCommon.register( 'Scale', Scale );
 export default Scale;
\ No newline at end of file
diff --git a/js/common/model/VerticalCylinder.js b/js/common/model/VerticalCylinder.js
index ad13e2bc..13cff8da 100644
--- a/js/common/model/VerticalCylinder.js
+++ b/js/common/model/VerticalCylinder.js
@@ -12,6 +12,7 @@ import Vector2 from '../../../../dot/js/Vector2.js';
 import Vector3 from '../../../../dot/js/Vector3.js';
 import Shape from '../../../../kite/js/Shape.js';
 import merge from '../../../../phet-core/js/merge.js';
+import IOType from '../../../../tandem/js/types/IOType.js';
 import densityBuoyancyCommon from '../../densityBuoyancyCommon.js';
 import Mass from './Mass.js';
 
@@ -270,5 +271,12 @@ class VerticalCylinder extends Mass {
   }
 }
 
+// @public {IOType}
+VerticalCylinder.VerticalCylinderIO = new IOType( 'VerticalCylinderIO', {
+  valueType: VerticalCylinder,
+  supertype: Mass.MassIO,
+  documentation: 'Represents a cylinder laying on its end'
+} );
+
 densityBuoyancyCommon.register( 'VerticalCylinder', VerticalCylinder );
 export default VerticalCylinder;
\ No newline at end of file