A thermoplastic polyester composition comprises polyalkylene terephthalate, a block copolymer comprising a semi-crystalline polyolefin block and at least one of a vinyl aromatic polymer block and an elastomeric polyolefin block, and reinforcing filler. IN the raised generally horizontal position a patient may be transferred to a chair or to a further horizontal structure such as a bed. The empty pan is temporarily expanded by applying vacuum to a bottom and sidewalls of the pan. The wire retention combs grip and secure portions of the discrete wires, and the registration block secures the ends of the exposed wires such that a stable connection between the wires and the electrical contact leads of the device can be maintained.