@Override
	public boolean isItemValidForSlot(int i, ItemStack stack) {
		if(MMHeatFuels.containsItem(stack.getItem()) && i == 1)
			return true;
		else if(MMUpgrades.containsItem(stack.getItem()) && (i == 3))
			return true;
		else if(i == 2)
			return false;
		else 
			return true;
	}