Pup Saver is the only crash tested rear facing dog car seat on the market. It was a pricey investment but worth the safety it provided my sweet small dog when he traveled with me. He didn’t go places too often but it was used probably 5-10 times and gave me peace of mind. I’ve included website photos, and instructions for install are on their website. It connects to seatbelts, etc. similar to a child car seat. Good for pups up to 30lbs.