As stated in The Unique Princess by Rabbi Yirmiyohu and Tehilla Abramov, “The halachic opinions that permit the wearing of wigs were talking about wigs that were short, unnatural looking, and “wiggy”. Such wigs were in use a century ago, explains Maran HaGaon Rav Yosef Sholom Elyashiv, shlita. They were short and stiff, and the hairs did not move from their place.” (page 103)
Further on it says, “Rav Elyashiv also clearly stated that in his opinion it is preferable for a woman to cover her hair with a kerchief rather than a wig. He constantly expressed his concern about the use of wigs that are not modest- a practice which, he says, has made inroads even into the families of pious men and roshei Yeshivah. ” (page 105)
This book has the approbation of many Gedolim including Rav Elyashiv, Rav Zilberstein, Rav Karp, Rav Scheinberg, Rav Ezriel Auerbach, Rav Ovadia Yosef, Rav Weinbach, Rav Zev Leff, Rav Asher Zelig Weiss etc…