Can I Disable 3G on 4S Like on 4?

[Pseudo-Fed]

Battery life on 4s is worse for me than 4. Noticed no button to select 3G. On the 4 I kept it on Edge unless needing the speed. Is there a setting? What about an app? Thanks.

 

[f4780y]

Looks like the option has gone on the 4S. I can't find it anywhere.

No other mechanism at the moment either, as we cannot jailbreak the 4S yet.