Cordless Doorbell

We've had one of these cordless doorbells for a number of years. If David needs assistance and I'm in another part of the house where I might not be able to hear him calling, he can have the button with him and I can have the chime with me. By adding velcro to the back of the button it can be mounted anywhere.
When my father came to need a home health aide, I got one for him.
Most recently my in-laws were in need of one as they couldn't hear the regular doorbell when they are in their den. This did the trick!