diff --git a/src/main/kotlin/ru/dbotthepony/mc/otm/container/Iterators.kt b/src/main/kotlin/ru/dbotthepony/mc/otm/container/Iterators.kt
index 815fc66b7..465be0375 100644
--- a/src/main/kotlin/ru/dbotthepony/mc/otm/container/Iterators.kt
+++ b/src/main/kotlin/ru/dbotthepony/mc/otm/container/Iterators.kt
@@ -3,8 +3,8 @@ package ru.dbotthepony.mc.otm.container
 import net.minecraft.world.Container
 import net.minecraft.world.item.ItemStack
 import net.minecraftforge.common.capabilities.Capability
+import net.minecraftforge.common.capabilities.ICapabilityProvider
 import ru.dbotthepony.mc.otm.core.ifPresentK
-import java.util.function.Consumer
 
 class ContainerIterator(private val container: Container) : MutableIterator<ItemStack> {
 	private var index = 0
@@ -30,10 +30,7 @@ class ContainerIterator(private val container: Container) : MutableIterator<Item
 	}
 }
 
-fun Container.iterator() = ContainerIterator(this)
-
-class NonEmptyContainerIterator(container: Container) : MutableIterator<ItemStack> {
-	private val parent = ContainerIterator(container)
+open class NonEmptyItemStackIterator(protected open val parent: Iterator<ItemStack>) : Iterator<ItemStack> {
 	private var itemStack: ItemStack? = null
 	private var searched = false
 
@@ -70,30 +67,29 @@ class NonEmptyContainerIterator(container: Container) : MutableIterator<ItemStac
 		this.searched = false
 		return itemStack
 	}
+}
 
+class NonEmptyMutableItemStackIterator(override val parent: MutableIterator<ItemStack>) : NonEmptyItemStackIterator(parent), MutableIterator<ItemStack> {
 	override fun remove() {
 		parent.remove()
 	}
 }
 
-fun Container.nonEmptyIterator() = NonEmptyContainerIterator(this)
-
-class ContainerIteratorCapability<T>(container: Container, private val cap: Capability<T>) : MutableIterator<Pair<ItemStack, T>> {
-	private val parent = NonEmptyContainerIterator(container)
-	private var itemStack: ItemStack? = null
+open class CapabilityIterator<P : ICapabilityProvider, T>(protected open val parent: Iterator<P>, private val cap: Capability<T>) : Iterator<Pair<P, T>> {
+	private var provider: P? = null
 	private var capability: T? = null
 	private var searched = false
 
 	private fun search() {
 		searched = true
 
-		if (itemStack != null) {
+		if (provider != null) {
 			return
 		}
 
-		for (item in parent) {
-			item.getCapability(cap).ifPresentK {
-				itemStack = item
+		for (provider in parent) {
+			provider.getCapability(cap).ifPresentK {
+				this.provider = provider
 				capability = it
 				return
 			}
@@ -105,28 +101,38 @@ class ContainerIteratorCapability<T>(container: Container, private val cap: Capa
 			search()
 		}
 
-		return itemStack != null
+		return provider != null
 	}
 
-	override fun next(): Pair<ItemStack, T> {
+	override fun next(): Pair<P, T> {
 		if (!searched) {
 			search()
 		}
 
-		val itemStack = itemStack ?: throw IllegalStateException("No next element")
+		val provider = provider ?: throw IllegalStateException("No next element")
 		val capability = capability ?: throw IllegalStateException("No next element")
-		this.itemStack = null
+		this.provider = null
 		this.capability = null
 		this.searched = false
-		return itemStack to capability
+		return provider to capability
 	}
+}
 
+class MutableCapabilityIterator<P : ICapabilityProvider, T>(override val parent: MutableIterator<P>, cap: Capability<T>) : CapabilityIterator<P, T>(parent, cap), MutableIterator<Pair<P, T>> {
 	override fun remove() {
 		parent.remove()
 	}
 }
 
-fun <T> Container.iterator(cap: Capability<T>) = ContainerIteratorCapability(this, cap)
+fun Container.iterator() = ContainerIterator(this)
+fun Iterator<ItemStack>.nonEmpty() = NonEmptyItemStackIterator(this)
+fun MutableIterator<ItemStack>.nonEmpty() = NonEmptyMutableItemStackIterator(this)
+fun Container.nonEmptyIterator() = iterator().nonEmpty()
+
+fun <T> Container.iterator(cap: Capability<T>) = CapabilityIterator(nonEmptyIterator(), cap)
+
+fun <P : ICapabilityProvider, T> Iterator<P>.filtered(cap: Capability<T>) = CapabilityIterator(this, cap)
+fun <P : ICapabilityProvider, T> MutableIterator<P>.filtered(cap: Capability<T>) = MutableCapabilityIterator(this, cap)
 
 inline fun <T> Container.forEach(cap: Capability<T>, consumer: (Pair<ItemStack, T>) -> Unit) {
 	for (value in iterator(cap)) {