From THEYESHIVAWORLD>

Rav Kanievsky Shlita on Wearing a Wristwatch

KanievskyHaGaon HaRav Chaim Kanievsky Shlita gives many people a bracha and advice when they visit with him seeking just that. The rav also frequently requests that they accept upon themselves something to uplift themselves spiritually, such as growing a beard and peyos. It appears that of late, Rav Kanievsky has also instructed people seeking his bracha not to wear a wristwatch to avoid “לא ילבש”. He points out that the Chazon Ish and his father, the Steipler, did not wear wristwatches because of the prohibition.
Longtime talmidim of Rav Chaim are quoted as saying this is not news, explaining they have been familiar with the rav’s position regarding a wristwatch.
Kikar Shabbat adds that last week, Rav Kanievsky was shown photos in which Rav Shach ZT”L and Rav Elyashiv ZT”L were wearing watches. Rav Kanievsky reportedly responded explaining that he too used to wear one until he received reliable eidus from Maran Chazon Ish that it is prohibited