That one certainly is inexpensive.

+/- 75' accuracy and not temperature compensated. I would not recommend it.

ebay has a Thommen listed which is vastly superior.

http://cgi.ebay.com/Thommen-SWISS-HANDHE...1QQcmdZViewItem

An cheap altimeter is just not worth the money in my view. Compass and altimeter navigation requires excellent instruments and most of the cheap altimeters are more toys than instruments.