Anyone who rides to work or sets off on a trip will have already experienced that in your helmet, you can be completely alone. Sometimes this can be useful, at other times you want to feel that there is an outside world.
The SF1 offers everything you need, without having to buy a full-fledged (and more expensive) intercom system, of which you won't use half the functions. The SF1 connects to your phone via Bluetooth - and therefore wirelessly. Streaming music, listening to the GPS-function, even a normal old fashioned phone call, it is all possible. You control the whole thing through speech, so you don't have to fiddle with buttons and can stay focused on the road.
In other words, the SF1 is the basis. Simple, convenient and full-fledged, as long as you don't expect to communicate bike to bike with your group or travel companions on the road (but possible with a passenger!). If you do, then the SF2 and SF4 are better options. In all three cases it's a streamlined, slim and handy device, which should fit in just about any helmet.
With Bluetooth V4.1, stereo sound, electronic wind noise reduction, quick charge system (1.5 hours), about 13 hours talk time and a stand by period of seven days, the SF1 delivers a lot for relatively little money.
Attention: Intercom driver -> passenger only possible from firmware version 2.0.
General remark: The world of electronics (which also includes intercoms, smartphones, gps, etc.) changes so quickly that it is possible that some (outdated) devices are not compatible with each other in certain areas. Unfortunately, the manufacturer can't provide us with data that shows which combinations between intercoms/gps's and/or smartphones cause problems. A regular update of all electronic devices is therefore desirable to avoid problems as much as possible.