It's not just that it's hard plastic: you're supposed to get them big enough that they can't get their jaws around them either. I bought one for Bongo when she was little, but she just wasn't bothered with it, and it's got lost along the way. Shame really, cos I think Roly would love it

Just had a look at these.
Didn't realise I can get them from my supplier.
But after what a few people have said........not sure if I should!!