The 'Thunderpole 1/2 Wave Silver Rod' is a classic design of CB base station antenna that has been tried and tested for over 30 years. The simple aluminium construction is a full half wave on 27 MHz, meaning a low SWR reading is easy to obtain.
The antenna uses a 'no ground plane' design allowing simple mounting in many situations. It will perform well in most circumstances and won't be beaten on value for money, it is easy to see why it has been the best selling CB base antenna for many years.