At my hospital we don't use slings as they encourage disuse and internal rotation contractures. On rare occasions we may make a sling to assist with transfers only if the person has a flaccid arm. The sling is removed immediately after the transfer. If someone needs an external support we get neoprene supports that go over both shoulders. They look a bit like a shoulder holster. If someone has a flaccid arm and palpable subluxation we also use FES on posterior deltoid for up to 6 hours per day.