I picked up three T35 heads last week and I can safely say that they are one of the best heads that I have ever used. My guys love them and I thought that I would pass along the enter workings to show the ups and down of these heads. Phto 1. This part of the head screws to the trimmer shaft. The spring is contained within the attached blue button. These two parts do not seperate which does away with having to mess with or lost springs. The blue Button when pushed makesa 1/4 turn to advance the line. Note the grooves in the button. More on them later. Photo 2. The spool. Note the grooves on the inside. These are what engages the blue button on the head. When the button is tapped on the ground to advance the line. Both the spool and the button turns as one. The two shorter grooves (only one showen here) are for the "nipples" inwhich the line inserts. Photo 2A. This is the spool on edge. They do not hold as much line as other spools. The "nipples" as we have came to call them can be seen here. I have tried .80 and .95 line and it is simple to insert both into the nipples. The only thing I and my guys do not like about the spool is amount of line it can hold. Photo 3. The cap. It is much like the Stihl 25 head. Push two tangs on the head to release. The line guides can be removed and flipped over when wear accures and line cutting starts to take place. Hint to all head manufactors... Make the line guides out of a good quailty Stainless Steele instead of Aluminum if you want to really improve a trimmer head. --------------------- Overall. We love these T35 Heads. For you can remove the spool, reload with line and never have to flip the trimmer on its top. Simple and very easy to use. So far they have stood up well without a hint of trouble. I can not give a durability report on how well that they will hold up for the long haul for I have only had them for a week. But well worth a look if you want an easy head to reload without having to filp your trimmer. These cost me $24.00 at the local Lowes store in Charleston, WV.