We report an experimental study on a new arrangement of flow focusing that uses a slit aperture. The slit can achieve similar flow chocking function as a classic circular aperture to established gas flow pressure drop. Fundamentally, the jetting mechanism and quantitative behavior of slit flow focusing are very similar to the classic flow focusing because of the singularity nature of the jet despite the drastically different aperture shapes. After re-scaling the jet shape, the axial coordinate with the hydraulic diameter of the slit, the experimental data follow closely with the universal jet profile derived in Gañán-Calvo, Ferrera, and Montanero [“Universal size and shape of viscous capillary jets: Application to gas-focused microjets,” J. Fluid Mech. 670, 427-438 (2011)] based on circular aperture. Practically, the slit configuration expands the possibility of manipulating the jets. The two thin plates that form the slit aperture can also be used as electrodes to apply electrohydrodynamic excitation to the jet for controlled jet breakup with narrower droplet size distribution. In addition, the modest throughput of a single flow focused jet can be increased by operating a linear array of jets focused and excited by the same slit.