Top Reviewer Ranking: 4,729,513
Hewlett Packard HP50G Graphing Calculator by HP
5.0 out of 5 stars Astonising, 8 Feb 2013
I had already used a HP 49 but I had to change it.
It's works perfectly ok and faster than the previous one.

I strongly recommend it for anyone who is looking
for a great and efficient scientific calculator.