I bought this for use at work: a SNF. It takes about 5 seconds longer than a $200 version that my boss has, but it still works well as a baseline reading at rest, which is most of what I need it for.
My children loved testing it out, too.
It's small and portable. It's expected to last about 3 years, according to the instruction manual.
It needs 2 AAA batteries that are not included.