As early as 1938, among the first technologies developed to address toilet training was known as the "bell and pad", where a sensor detected when a child had wet themselves at night, and triggered an alarm to act as a form of conditioning. Similar alarm systems have been studied that sense wetness in undergarments, especially as it concerns the toilet training of those with intellectual disabilities. This has been applied more recently in the production of potties, that play an audible cheer or other form of encouragement when used by a child.: 170–2 Trainers may choose to employ different choices of undergarments to facilitate training. This includes switching from traditional diapers or nappies to training pants (pull-ups), or the use of non-absorbent cotton underwear of the type adults may wear. These are typically employed later in the training process, and not as initial step.: 175  Children who experience repeated accidents after transitioning to cotton undergarments may be allowed to resume the use of diapers.Most widely used techniques recommend the use of specialized children's potties, and some recommend that parents consider using snacks or drinks as rewards.