QUESTION: How do the trimmers attach to the tool rack? ANSWER: The "collars" you see the on the trimmer rack that the trimmer shaft is mounted to are actually mounted to your string trimmers. When you take the trimmer off the rack, the collars come off the rack with it. They stay mounted on the trimmer shaft while you operate the tool. When you are finished, simply insert the trimmer and the red collars back into the recievers on the trimmer rack, and lock it. While this involves clamping the collars to the trimmer and leaving them on, it makes for a secure fit that ELIMINATES ROLLING while mounted in the rack.