Tar resistant nose (patent pending). The nose of the CN445R is designed to resist tar four times longer than conventional tools. This equates to less time spent cleaning the tool and more productivity * Maintenance free end cap filter (US patent 5637125) captures dirt and sand down to microns but lets oil and air into the tool. Filter keeps inside parts clean and lasting longer than competitors tools with out filters * Dial adjustable depth control dial depth control requires no special tools, providing accurate depth control