The utility of portable computer hosts, such as PDAs, is enhanced by methods and apparatus for removable expansion cards having application specific circuitry, a second-level-removable memory, and optional IO, in a number of illustrative embodiments. Provision is made for an adjusting device to displace the brush arrangement as a function of the switch position of the mode selector switch. Most importantly, the freeflex sports cap is water resistant; making it a valuable head protective gear during any unexpected weather changes. Various processing environments can be employed in the system.