XMark 12 Decline Ab Bench XM-4416. Click on the photo to check the Price on Amazon. One of the most common recommendations you hear from exercise experts when you ask about ab exercises, is to get an ab bench for your crunches, situps and other workouts. The XMark XM-4416 is the best Groom+Style found. It’s made from 14-gauge 2-by-3 inch steel, so it’s exceptionally strong – strong enough to handle 400 pounds.