Adult diapers come in light, moderate, and heavy absorbency. If you want, even more, there is the overnight type. It is called overnight because it is meant to be used at night when there is less changing of the incontinence product. Overnight products sometimes absorb up to thirty-four fluid ounces and beyond. Keep in mind an adult bladder only holds sixteen fluid ounces.
There isn't really an absorbency category above overnight, though some products go far farther than others. One abri-sans pad actually holds up to 67.6 fluid ounces. However, this is the exception rather than the rule. Most incontinence products don't label exact fluid ounces, so you can look for 'overnight' or 'heavy to overnight'.
For even more protection, in case the product is not enough, look for liners or booster pads to increase the amount of absorbency. Covers are less effective but can work. Also, you can protect bedding with underpads. All this is usually not necessary, but it certainly can be. If you are doing a lot and it is not working, consider changing your style or brand. Overnight products come in a large range of sizes, from youth to plus size.