I have several of the 2510 trimmers with the "Brain" trimmer heads. I am having problems with the cap portion falling off. This happens on while on the rack on my trailer probably due to the vibrations from the road. I have lost these "caps" off of both new and old trimmer heads. If I lose only the cap then it becomes a $20 repair. If I lose the inner spool too, then it just makes more sense to buy an entire new head. Growing tired of what seems like a money pit I have searched for a replacement head that will fit. Landscapers Supply Corp. sold me a head that was supposed to fit, except it was a "male" rather than "female" mount. I would rather convert all of my trimmer heads than replace all of my trimmers, but there doesn't seem to be any solution. I have been in business doing commercial work for 18 years and I have not had another manufacturers trimmer fall apart like this. My local dealer is more than willing to just continue selling these parts to me, but I am tired of it. How much work can you get done if you show up to a clients site with only 90% of a string trimmer?