Tool - Laser Measurer
DEWALT DW03050 165-Feet Laser Distance Measurer
Available for about $108 from:
http://www.amazon.com/DEWALT-DW03050-165-Feet-Distance-Measurer/dp/B00FKMS2WG
Manual: https://images-na.ssl-images-amazon.com/images/I/A13IF9toJWL.pdf