There are so many kinds of "diapers" or Adult Briefs. Usually if it's a heavy incontinence situation. You can use a diaper with tapes, and some have "velcro" Either paper facing or plastic. With paper facing it's more breathable and comfortable than plastic which may be noise and builds heat during the summer months.
You can also look in to Pull Up/Protective Underwear which are just like underwear which you can slip on and off or rip the sides if you need to remove them.
The absorbancy comes from a polymer that gels up when it becomes wet, so a thicker diaper is not necessary a dryer one.
You also need to make sure that the size is right otherwise it will leak and bigger is not better.
Depends is the big name brand but they are not as absorbent as Tranquility, Prevail or Attends.
Give CWI Medical at www.cwimedical.com a call for samples. Or Try HDIS, Or Woodbury
Goood Luck! and I hope this helps