Question: What do those tiny string holders (e.g. String-a-Lings or String Savers) do?
Answer: String holders are intended to keep the main strings from shifting upon ball impact, especially on spin strokes. Preventing shifting enhances spin, as does the extra texture the string holders add to the string bed. By keeping the strings from rubbing one another, the string holders should, in theory, also prolong the strings' lifetime, but some argue that they concentrate stress at one point along the string, causing it to break sooner.