If you want to just make the in and out of the trunk a lot easier, check out the Twistep. I've used a bunch of different step and ramp products over the last few years and this is one of my favorite honestly. Made life easier for my Great Pyrenees when he got geriatric and am now using it for my Tibetan Mastiff who is 7 and my Newfoundland who is young but tends to slam his body into my bumper
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Dog Ramp for SUV | Best Dog Step | Dog Stairs for Truck | Twistep