Astro Pneumatic Quick Change In-Line 4” Cut-Off Tool 409 Astro Pneumatic Quick Change In-Line 4” Cut-Off Tool 409 is designed with a quick change button on the housing that locks the motor for easy disc changes and the in-line design allows for straighter and naturally consistent cuts. Astro Pneumatic Quick Change In-Line 4” Cut-Off Tool 409 features a 3/4HP Motor and a 4” size for maximum cutting capacity, a lever lock safety guard that quickly and easily adjusts. Astro Pneumatic Quick Change In-Line 4” Cut-Off Tool 409 works well with most 3/8” and 5/8” hole cut-off wheels and includes one 4” cut-off wheel.