I have 2 sets of these (bought for our then 4wk old and 18 month old). Tried them on again this summer - they are now 3 and 4.5yrs and they were too small. However! My husband worked out that its the black poles at the SIDE of the ears that do in fact extend - and not the top bands. Honestly, now even I can fit my head in them!! So, after all, they are adjustable and I'm off to buy an another pink set for our 3rd child, rather than the adult version I thought I needed for our big-headed older child! (She wears age 7-10 hats). I hope I have helped you, as this has taken us 2 years to work this out too!! Grr!