I bought the Allsafe dog seat belt after it was recommended to me by my brother who has a labrador. It comes in three sizes - small, medium and large. I bought mine online at a cost of £36 which included postage and packing.
My dog is a Shih Tzu and regularly accompanies us on car journeys. I hated having to put him in a crate in the back as it upset him. I bought the small size and it arrived within a few days. When it arrived, I was immediately impressed as it was very sturdy and well padded, which meant that it would be very comfortable for our fur baby.
Our dog was much happier travelling with this harness and he was very safe without feeling too restricted. The length of the straps are easily adjusted which means that it can be fitted to suit the dog keeping them and the driver totally safe. Very secure fitting and I felt that my dog was safe and happy. When not in use while travelling, the harness can be used when walking the dog in everyday situations. Reflective strips for added safety.
One thing I would say is that the small size fitted our dog in length, but was slightly loose around his chest area, but not enough to allow him to escape. I was expecting it to be a more snug fit, but this would not have prevented me from buying it or recommending it to other dog owners.