Sandpaper or split mandrels have a "split" above the reinforced base allowing the user to wind sandpaper, polishing cloth, or other abrasives around the gap. These mandrels come in tapered style and generally used to sand in tight spots. The tapered one offers access to undercuts. Maximum and recommended speeds depend on the type and size of accessory, as well as the mandrel in use.
As a general rule, smaller accessories and mandrels can be used at higher speeds than larger accessories and mandrels. 3/32" head diameter, 3/4" slot length, 1/64" slot width. 1-3/4" overall length. 20,000 RPM Max Speed.