Handheld Offroad Radios come in .5 Watts up to 5 Watts of power depending on the frequency band selected. Handheld walkie talkies are convenient as they're battery powered and can be moved from vehicle to vehicle easily but do not have the same operating range as mobile two way radios.
Mobile two way radios come in 2 watts all the way up to 50 watts depending on the frequency band selected. Mobile two way radios are either fix mounted to a vehicle or can be converted into a base station.
Repeaters allow for extended range and are a good option for Clubs, OffRoad Parks, and RaceTracks. Repeaters always require an FCC license and are avaiable in 5 Watt and 50 watt configurations.