A metronome builds rhythmic stability and is a required tool for pianists to succeed.
Recommended Options If You Need a Metronome:
1) Apps: Before you purchase another gadget, take advantage of the inexpensive apps available for your smart phone or iPad/tablet:
Tempo Metronome by Frozen Ape $1.99
A good one!
Yes, this app counts ALOUD for you in the voice of your choice, even Darth Vader!
Can't beat the price a a very easy to use app!
2) Metronome: In case you need one and don't have a smart phone, here's one I'd recommend. It can be purchased at Amazon or Music and Arts.