If you already own the two-way radios, firstly you need to make sure that the headset you’re looking at is compatible: visually inspect the radio to see if there is a headset port on there - it is often hidden under a waterproof rubber seal. Check your radio make and model, confirm the connector type, and then decide on the wearing style you need for your uses.
A Bluetooth walkie talkie headset is an option for when the staff are on the move and could be hindered by wired solutions.