These devices are expensive, but well engineered, and have features that others often don’t (such as a two socket outdoor pocket socket, although they turn on and off together, not independently). They also also work with HomeKit for those interested in that.
Note that the Instant Switch only works as an accessory switch for one of their other devices. You can’t use it on its own. It’s still a nice device, but it’s basically just a remote for the master.
Prices vary a lot, so check Amazon as well.