Dr. Pen Ultima M7 Micro Needling Derma Pen - Including 20 Pcs CartridgesDr. Pen Ultima M7 Meso Micro Needling Machine Derma Pen Dr Pen Ultima M7 microneedling pen is used mostly for face wrinkles, scars, stretch marks, and facial lines. Dr Pen uses sterile, individually sealed, disposable needle cartridges for optimal safety and comfort. The adjustable dial allows treatment that adapts to individual clients needs. Dr Pen is more economical than the derma roller, you just need to recharge the pen and replace cartridges