Many of us lift and carry sheets of plywood, homasote, etc. This "gripper" makes it a lot easier for me to get panels into my basement. There are cheaper types that hold sheets from the bottom, but my back won't take it any more.
Here's one source. They cost $40.
http://www.amazon.com/Gorilla-Gripper-44010-Panel-Carrier/dp/B
While I'm at it, here's 2 layout-building photos. I paint plywood a dark color to see where tracks are from underneath my layout:
A silver mine spur:
Terry
Oops! The link does not work. Go to Amazon.com and enter 44010 in the Search box, or Google "Gorilla Gripper" for another source.