diff --git a/eco-core/core-plugin/src/main/kotlin/com/willfp/ecoarmor/sets/ArmorUtils.kt b/eco-core/core-plugin/src/main/kotlin/com/willfp/ecoarmor/sets/ArmorUtils.kt
index 9e7a57a..55716be 100644
--- a/eco-core/core-plugin/src/main/kotlin/com/willfp/ecoarmor/sets/ArmorUtils.kt
+++ b/eco-core/core-plugin/src/main/kotlin/com/willfp/ecoarmor/sets/ArmorUtils.kt
@@ -202,13 +202,13 @@ object ArmorUtils {
             tier.id
         )
         val slot = getSlot(itemStack) ?: return
-        val armor = tier.properties[slot]!!.armor
-        val toughness = tier.properties[slot]!!.toughness
-        val knockback = tier.properties[slot]!!.knockback
-        val speed = tier.properties[slot]!!.speed
-        val attackSpeed = tier.properties[slot]!!.attackSpeed
-        val attackDamage = tier.properties[slot]!!.attackDamage
-        val attackKnockback = tier.properties[slot]!!.attackKnockback
+        val armor = tier.properties[slot].armor
+        val toughness = tier.properties[slot].toughness
+        val knockback = tier.properties[slot].knockback
+        val speed = tier.properties[slot].speed
+        val attackSpeed = tier.properties[slot].attackSpeed
+        val attackDamage = tier.properties[slot].attackDamage
+        val attackKnockback = tier.properties[slot].attackKnockback
         meta.removeAttributeModifier(Attribute.GENERIC_ARMOR)
         meta.removeAttributeModifier(Attribute.GENERIC_ARMOR_TOUGHNESS)
         meta.removeAttributeModifier(Attribute.GENERIC_KNOCKBACK_RESISTANCE)
diff --git a/eco-core/core-plugin/src/main/kotlin/com/willfp/ecoarmor/upgrades/Tier.kt b/eco-core/core-plugin/src/main/kotlin/com/willfp/ecoarmor/upgrades/Tier.kt
index 6323470..12f35ad 100644
--- a/eco-core/core-plugin/src/main/kotlin/com/willfp/ecoarmor/upgrades/Tier.kt
+++ b/eco-core/core-plugin/src/main/kotlin/com/willfp/ecoarmor/upgrades/Tier.kt
@@ -10,6 +10,7 @@ import com.willfp.eco.core.recipe.recipes.ShapedCraftingRecipe
 import com.willfp.eco.util.StringUtils
 import com.willfp.ecoarmor.sets.ArmorSlot
 import com.willfp.ecoarmor.sets.ArmorUtils.getCrystalTier
+import com.willfp.ecoarmor.util.NotNullMap
 import org.bukkit.inventory.ItemStack
 import org.bukkit.persistence.PersistentDataType
 import java.util.*
@@ -56,7 +57,7 @@ class Tier(
     /**
      * Item properties.
      */
-    val properties: MutableMap<ArmorSlot, TierProperties> = EnumMap(ArmorSlot::class.java)
+    val properties: NotNullMap<ArmorSlot, TierProperties> = NotNullMap(EnumMap(ArmorSlot::class.java))
 
     /**
      * Create a new Tier.
diff --git a/eco-core/core-plugin/src/main/kotlin/com/willfp/ecoarmor/util/NotNullMap.kt b/eco-core/core-plugin/src/main/kotlin/com/willfp/ecoarmor/util/NotNullMap.kt
new file mode 100644
index 0000000..77c6958
--- /dev/null
+++ b/eco-core/core-plugin/src/main/kotlin/com/willfp/ecoarmor/util/NotNullMap.kt
@@ -0,0 +1,7 @@
+package com.willfp.ecoarmor.util
+
+class NotNullMap<K, V>(private val handle: MutableMap<K, V>) : MutableMap<K, V> by handle {
+    override fun get(key: K): V {
+        return handle[key]!!
+    }
+}
\ No newline at end of file