A trailer-mounted crash impact attenuator for attachment to a host vehicle includes an anti-rotational attachment system having an internal support tube and a plurality of external support tubes. The resilient stripper rubber body has a drillstring bore extending therethrough. The method includes angularly implanting a dopant of a second conductivity into the first sidewall, and angularly implanting a dopant of a second conductivity into the second sidewall. The other interrupt has a lower priority than the previously-received interrupt in the interrupt controller. The compositions are clear and do not foam when used in a recirculating fountain.