I have this one. It's a car harness. It's heavier and sturdier than a regular vest harness. The attachment lloops around the car seat belt and attaches on the harness, further down on the back than a regular vest harness. It's not fastened by velcro, like so many vest harnesses.
We use Look Out car seats here...not only do they boost the dog up so they can see out the window, but they come with a device that hooks to the dog harness/seat belt to keep the dog restraine. We put ours in the backseat in case of an airbag deployment.