diff --git a/CHANGELOG.md b/CHANGELOG.md
index e0d4de7..6df7d38 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,9 @@
 
 ## 0.0.21
 
+* Upfill `UIKitWidth`
+* New extension `UIKitModifier#applyWhenScreenSizeIs`
+
 ## 0.0.20
 
 * Remove type of button from `DefaultButton` and add companion to `UIKitButton` to be able to use `uk-button` class
diff --git a/src/jsMain/kotlin/dev/inmo/jsuikit/modifiers/UIKitScreenSizeModifier.kt b/src/jsMain/kotlin/dev/inmo/jsuikit/modifiers/UIKitScreenSizeModifier.kt
index 107aefd..f5e4248 100644
--- a/src/jsMain/kotlin/dev/inmo/jsuikit/modifiers/UIKitScreenSizeModifier.kt
+++ b/src/jsMain/kotlin/dev/inmo/jsuikit/modifiers/UIKitScreenSizeModifier.kt
@@ -18,3 +18,5 @@ sealed class UIKitScreenSizeModifier(val name: String) {
         modifier
     )
 }
+
+fun UIKitModifier.applyWhenScreenSizeIs(size: UIKitScreenSizeModifier) = size.modify(this)
diff --git a/src/jsMain/kotlin/dev/inmo/jsuikit/modifiers/UIKitWidth.kt b/src/jsMain/kotlin/dev/inmo/jsuikit/modifiers/UIKitWidth.kt
index c337369..724b879 100644
--- a/src/jsMain/kotlin/dev/inmo/jsuikit/modifiers/UIKitWidth.kt
+++ b/src/jsMain/kotlin/dev/inmo/jsuikit/modifiers/UIKitWidth.kt
@@ -3,8 +3,9 @@ package dev.inmo.jsuikit.modifiers
 sealed class UIKitWidth(classname: String) : UIKitModifier {
     override val classes: Array<String> = arrayOf("uk-width-$classname")
 
-    object Full : UIKitWidth("1-1")
+    object Auto : UIKitWidth("auto")
     object Expand : UIKitWidth("expand")
+    object Full : UIKitWidth("1-1")
 
     object Half : UIKitWidth("1-2")
 
@@ -12,22 +13,70 @@ sealed class UIKitWidth(classname: String) : UIKitModifier {
     object TwoThird : UIKitWidth("2-3")
 
     object OneFourth : UIKitWidth("1-4")
-    val TwoFourth get() = Half
     object ThreeFourth : UIKitWidth("3-4")
-    val FourFourth get() = Full
 
     object OneFifth : UIKitWidth("1-5")
     object TwoFifth : UIKitWidth("2-5")
     object ThreeFifth : UIKitWidth("3-5")
     object FourFifth : UIKitWidth("4-5")
-    val FiveFifth get() = Full
 
     object OneSixth : UIKitWidth("1-6")
-    val TwoSixth get() = OneThird
-    val ThreeSixth get() = Half
-    val FourSixth get() = TwoThird
     object FiveSixth : UIKitWidth("5-6")
-    val SixSixth get() = Full
+
+    sealed class Child(suffix: String) : UIKitWidth("child-$suffix") {
+        object Full : Child("1-1")
+
+        object Half : Child("1-2")
+
+        object OneThird : Child("1-3")
+        object TwoThird : Child("2-3")
+
+        object OneFourth : Child("1-4")
+        object ThreeFourth : Child("3-4")
+
+        object OneFifth : Child("1-5")
+        object TwoFifth : Child("2-5")
+        object ThreeFifth : Child("3-5")
+        object FourFifth : Child("4-5")
+
+        object OneSixth : Child("1-6")
+        object FiveSixth : Child("5-6")
+
+        object Auto : Child("auto")
+        object Expand : Child("expand")
+
+        companion object {
+
+            val TwoFourth get() = Half
+            val TwoSixth get() = OneThird
+            val ThreeSixth get() = Half
+            val FourSixth get() = TwoThird
+            val FourFourth get() = Full
+            val FiveFifth get() = Full
+            val SixSixth get() = Full
+        }
+    }
+
+    sealed class Fixed(suffix: String) : UIKitWidth("fixed-$suffix") {
+
+        object Small : Fixed("small")
+        object Medium : Fixed("medium")
+        object Large : Fixed("large")
+        object XLarge : Fixed("xlarge")
+        object XXLarge : Fixed("2xlarge")
+
+    }
 
     override fun toString() = classes.first()
+
+    companion object {
+
+        val TwoFourth get() = Half
+        val TwoSixth get() = OneThird
+        val ThreeSixth get() = Half
+        val FourSixth get() = TwoThird
+        val FourFourth get() = Full
+        val FiveFifth get() = Full
+        val SixSixth get() = Full
+    }
 }