battery monitor

anybody here have one of these?

[url]http://www.amazon.com/dp/B0029VY4G4/ref=asc_df_B0029VY4G42047312?smid=ATVPDKIKX0DER&tag=hyprod-20&linkCode=asn&creative=395093&creativeASIN=B0029VY4G4&hvpos=1o3&hvexid=&hvnetw=g&hvrand=20244700561994659618&hvpone=&hvptwo=&hvqmt=[/url]

if so, what kind of 'life remaining' numbers do you get?
thx,
ed

I have one; it shows 27% of life remains in my 4 yr old Westco battery.

Just ordered one from Defender.com for $40 plus shipping. Hope I will be a satisfied customer.