How do I find out which one I needEasy to pop them out. There is a tool ( Paramount Large Nozzle Tool - Plastic (PCC2000/Vantage/Vanquish) ) that makes it easy to pull them out. I have heads that stick up sometimes and they just need to be pulled out and then placed back in... this is due to debris getting into them. Just note that the link I provided may not be to your correct heads, but just to give you an idea of the tool.