Coreshell particles having a core of a porous polymer and a shell of an inorganic colloid, the inorganic colloid having a median diameter of less than about 0. The convertible seat is low profile and maintained flat on a side of the crutch until needed. Such data include EPG data, data broadcast data, print contents data and supplementary information on the print contents data. For calibration, marks or spaces are written adjacent to spatial features, with a range of times for initiating the writes. The method of making the muffler apparatus includes the selection of tubing constructed of such PEEK corrugated construction and the open cell polymer noise attenuation construction, telescoping the tubes together and securing the end fittings thereto. In one embodiment, the sensors can include micro-mechanical structure supporting electronic circuitry.