The 17 inch I have caps (plugged straight into an outlet) at 89º it is a low temp system I use it for cool end control as even in a runaway it is unlikely to burn my animals, I use 11" for hot sides the 17 just will not do it. My specs say it is only 10 watts per foot however it might not be the same.

http://www.cornelsworld.com/ look under for sale under the left side panel it states

"This heat tape does not get as hot as the 11". Heat on the 17" tape runs about 86 degrees. Would work well for warming mats at shows but not as heating elements on cages"