Special DVR are also known as Mobile DVR. They perform the same functions of a conventional DVR but imbedded with the ability of mobility. It is widely recommended for CCTV systems placed within transportation mediums such as buses, trains, boats, etc. Most of them are covered with vibration-proof and collision-proof casing, which allows extra protection for the system. The storage media of videos will be best protected in these DVRs. They also have an optional built-in 3G and GPS module.