Q. Can one sleeping in a Suka on Shabbat and Yom Tov wear the recently available watches or bands that emit ultrasonic waves to repel mosquitoes, bees and other harmful insects?
A. Horav Shlomo Miller’s Shlit’a opinion is that they are not muktza when needed and are similar to the common electric watches.
Although many maintain that those watches and bands are ineffective, if one wants to use them anyway, he is permitted to do so.
Rabbi A. Bartfeld as advised by Horav Shlomo Miller and Horav Aharon Miller Shlit’a