New F4-A model has robust aluminum curtainsider rail profiles. This solution enables maximum space utility ( rail dimensions are  43x160mm) and high construction strength. Patented frame construction enables easy and reliable tarpaulin roof opening and closing. The key element of this construction is multi layer rubber band that is capable for long term operating with numerous opening and closing. Center pillar rollers locks automatically when the pillars are fastened. Rear end opening is easy and functional due to gas springs relief.