I've been looking at gas pole pruners-- extra long. I looked at stihl and shindaiwa. I have a shindaiwa 377 chain saw. It's 4 yrs old. gets a lot of use and ALWAYS starts. DURABLE DURABLE DURABLE. I talked with a seller and said could buy the weed wacker, take off the wacker and buy (or exchange) for the extension housing then attach the extension pole and will get 12ft. Not rec by manufac. He uses as rental.. Then I came across the Echo that extends to 17' and has a 5ft extension. the stihl and shindaiwa use a steel shaft to turn the impliment. the sthil uses a square hole to connect shafts and the shindaiwa uses a 6-spline shaft. The Echo uses a HD cable and this is were I believe they can get their length of 22ft b/c less weight along the extended shaft means less bowing and therefore less likely to cause problems associated with bowing. If anyone has an echo which is the PT 260 and 5 ft extension bar, I like a review of it if possible