As an extra, or for anyone who needs a low cost instrument, I recommend the Kobalt LDM-35.
Available at Lowe's for $69 and online for less
Range of 115'
2xAAA
Gave consistently identical readings as Bosch GLM50 and GLR225
Lifetime Warranty
I've had no trouble with it so far. While the warranty won't be a huge comfort if it breaks and stops your survey, Lowe's (and possibly other retailers) is very good about replacing Kobalt stuff.