Not the OP but, I use a $6 one without a button that simply activates on insert. Unfortunately the company that sold them is more interested in bulk sales and the stopped selling individual units. I plan to eventually replace it with the Feitian ePass NFC FIDO U2F Security Key, which is still $17 but includes NFC which I could use with my android phone. for that functionality from Yubi you would need the $50 Yubikey Neo.