The Penta Ray was a weapon developed by the people of Solturis.
It fired a combination of Alpha, Infra, Omega, Ultra and Beta rays. It had not been used in one hundred years prior to the arrival of the Daleks, who stole the weapon and substituted a fake Penta Ray in its place. Geltis offered to give the Daleks the operating key, but then turned the weapon against them. After Geltis died, Jareth used the Penta Ray to destroy the Daleks. (TV21: The Penta Ray Factor)