This device is used to take the weight off the tongue of the towing vehicle, usually a motor home, protecting the towing vehicle from chassis damage, suspension strain and body flex. The 5000SD is built for large stackers and long haul towing. List price is $4995.We have used ours 4 times na it worked perfectly, even with a light load. Currently we use it to tow our trailer with a race car in it with a truck and extra long Lance truck camper.