This string trimmer head has been kind of frustrating for me. It's this one, the "Pro-Torque Trimmer Attachment" http://www.echo-usa.com/Products/Pro-Attachment-Series/99944200545 I guess i'm not 'pro' enough to use this. It's really only fed correctly when it was on the first factory spool of string. I have never been able to string it correctly since. I take a 20ft piece of string, pull it through the hole so it's halved, then wind it in the direction of the arrows, trying to keep the two parts as separated as possible. No matter what happens, the thing gets stuck inside at some point multiple times throughout the spool. Sometimes it feeds, sometimes it doesn't. Pretty frustrated. I did notice that the Echo factory used two strings, rather than one to string it. I don't know if that matters. I spent a lot of money on my PAS-266 and head attachments. Thanks for any advice you can offer on this seemingly trivial matter.