You have indicated that you are looking for walkie-talkies for a security organization that has a maximum of 7 floors or is less than 700 meters. In this case, a license-free Kenwood two-way radio is the best choice! The most sold two-way radio for this question is the Kenwood TK-3501. We may also have the Kenwood TK-3401. This is a digital walkie-talkie and has better audio quality and slightly more range. This is especially useful if you are not sure about the range.