On-hook, On-hook Cargo, Motor Truck Cargo and Garagekeepers are all different ways of providing coverage for the vehicle being towed or transported and it's contents(the freight in a truck) or cargo on your flatbed or trailer such as construction equipment. You need to read the particular form from each carrier to see how they would respond. With some carreirs you use garagekeepers and a motor truck cargo policy to cover the vehicles and cargo, the next it may be On-hook Cargo since that is how that program is designed and the next the On hook only covers the vehicle and carrier has a seperate cargo option which I don't use because it provides poor coverage, so I use a Motor Truck Cargo policy from another carrier for a better combined product. Garagekeepers provides coverage for "auto & auto equipment", and does not provide coverage for the cargo even though I have had may an agent tell their client that it does. They have never read the form. I have seen On hook forms that have overload exclusions- winch a 4,000 lb car onto a flatbed with a 3/8 cable with a 3500 lb safe working load and have the cable break and the car rolls back into a building, the carrier could deny the claim. Ask your agent to read the form with you and explain how it will respond to different types of claims. This is just a quick overview of some of the different cover forms, there is a lot more to this. You can't make a blanket statement on how on-hook works.