1. When you change the degree of pressing the devolt button, unlike brush models, the rotation speed changes in steps, with a certain step, and not smoothly, and this is not very convenient if you need accurate dosing of force. 2. Backlash, the beating of the bit is quite strong. Conclusion: this is rather a power model for rough work, twisting boards at a construction site, drilling thick metal plates, fine work can also be done, but it's like shooting sparrows with a cannon .