Maybe it's E-7017,

Hey Mana,
Welcome to the AWS Forum.

-1 doesn't make sense.  It's usually alpha numeric.  Example -A1, -B4, -C3 etc

Tyrone

WELCOME TO THE ORIGINAL AWS WELDING FORMUM!!

Electrodes with that designation have enhanced impact values at lower temperatures.  20 lbs @ -50°F instead of the normal 20 lbs @ -20°F for most 7018 electrodes. 

Go here to read about the designator:

http://www.hobartbrothers.com/index.php?mact=News,cntnt01,print,0&cntnt01articleid=154&cntnt01showtemplate=false&cntnt01returnid=523

And here to read about Lincoln's electrode with it:

http://www.lincolnelectric.com/en-us/consumables/Pages/product.aspx?product=products_consumable_stickelectrodes-mildandlowalloysteels-excalibur-excalibur7018-1mr(lincolnelectric)

He Is In Control, Have a Great Day,  Brent