OWL is a water-dielectric line-type pulse generator capable of producing ∠100-nsec electron beams with total energies of as much as 150 kJ. In its present form, OWL II consists of an oil-immersed, 1/3-MJ Marx generator charging a 3.9-Ω coaxial pulse-forming line which is series switched into either a two- or three-stage impedance transformer. The output impedance is 1.9 or 1.1 Ω, depending upon which transformer is used, and nominal beam outputs in the two cases are 1.3 MV at 0.8 MA and 0.9 MV at 1.2 MA, respectively. The pulse width can be selected at either 60 or 120 nsec (FWHM of power) by interchanging two available pulse lines. Shot-to-shot reproducibility in output of ±2% with a mean electron energy ∠1.0 MeV is obtained with the 1.9-Ω final transformer. A triggered multichannel water switch minimizes the risetime of pulses injected into the transformer section.