I have a Electricalc LT, which is made by Calculated Industries, but is an older model. I traded a Projectcalc? for it with a GC who had won the Electricalc at a trade show.
For anybody who hasn't used the Projectcalc type units, if you do layout on new buildings, it is a must have, allowing you to add feet, inches, yards, and fractions all at the same time.
The Electricalc I have, I loved. Voltage drop problems became fun, wire size, ground wire size, anything you could want to know is available and easy to find. I say I loved it, not I love it, becouse it stopped working properly. One row of keys stopped working, I don't know if it was a software or hardware issue, but it was a fatal error.
I have missed it, and have intended to replace it for a long time.