speaker wire size for in wall speakers

[fatboyracing]

I am getting a set on dayton in wall speakers they are the Dayton CS620W
I am going to only send them 50watts the rms is 60 watts

it will be about a 40 foot run to each speaker what is the smallest wire that will be good for this

[jdawg]

http://www.bcae1.com/wire.htm

[fasfocus00]

you could get away with some nice 18 gauge but i'd use 16 gauge.