The ST-3 is the only rack designed specifically for the STIHL 350, 430 and 450 (New Style) blowers. Simply set your blower on the lower posts and pivot the top toward the rack, allowing the "sliding lip" to, slide under the handle. Complete installation by pulling the ball knob on the rack and lowering the "sliding lip" over the blower. The blower is secured at the top and bottom and will not move around.