I got this for my 4 month olds Christmas present and 6 weeks on it's still easily his favourite toy. He's very active and needs constant interaction and entertainment but if I need 10 mins to sort something he is so happy quietly exploring this with his mouth. I've even started taking him along to gym classes and he plays with this for the full hour whilst watching what's going on. And the noise from it attracts a lot of jealous babies that want a shot!
Very happy with this, will look at other bits from yummikeys too