Systems and methods are provided to facilitate retail transactions via mobile communications. The composition contains a transparent thermoplastic polymer and one or more compounds conforming to formula 1wherein R1 to R40 independently denote a member selected from the group consisting of H, alkyl, halogen and CN. In the first, turning mode, an operator is able to steer the vehicle left, right, or straight by independently operating the first and second traction devices via the first and second steering inputs. The Bessel filter is an n-pole recursive digital filter, which is expressed as a ratio between an order polynomial of a complex number and an n order polynomial of a complex number, where n is a positive integer. A spanning member is disposed in each of the slots such that the sections and the spanning members cooperate to form a continuous cover member that surrounds the selected portion of the shaft. The contact strip is formed in an inverted V sectional shape, and has sloped walls at both left and right sides thereof.