Here you see the difference between the biggest SuppleNipps 5XL and 4XL. I like to use both both but I do like the shape your nipples get when you use smaller nipple suckers. Unfortunately the XL versions of SuppleNipps are not produced anymore. You might find them still in stock of some adult shops. The producer only makes the shorter versions now and sells them via Amazon. But I think the shorter SuppleNips (with one p) are perfect for beginners though.