The pads are not the same as incontinence pads, which generally have higher absorbency and are worn by those who have urinary incontinence problems. Although menstrual pads are not made for this use, some use them for this purpose.
Panty liner: Designed to absorb daily vaginal discharge, light menstrual flow, "spotting", slight urinary incontinence, or as a backup for tampon or menstrual cup use.
Ultra-thin: A very compact (thin) pad, which may be as absorbent as a Regular or Maxi/Super pad but with less bulk.
Regular: A middle range absorbency pad.
Maxi/Super: A larger absorbency pad, useful for the start of the menstrual cycle when menstruation is often heaviest.
Overnight: A longer pad to allow for more protection while the wearer is lying down, with an absorbency suitable for overnight use.
Maternity: These are usually slightly longer than a maxi/Super pad and are designed to be worn to absorb lochia (bleeding that occurs after childbirth) and also can absorb urine.