The phrase "very thing" refers to something that is precisely what is needed or desired. Synonyms for this phrase include "perfect fit" which means a solution or idea that is exactly what is needed or desired. "Exact match" describes something that is a precise replica or counterpart, and "ideal choice" suggests that a selected option is the very best possible one. "Excellent selection" is another synonym, conveying the idea that there were several alternatives but this one stands out above the rest as the best. "Just right" is a more informal synonym meaning that something is neither too much nor too little, but just perfect.