This is a fairly amazing little setup -It's very specific to upgrading or repairing a sewing machine - not something that "could be used" but actually purpose designed and built - specifically for a sewing machine.The bracket and mounting are light weight but very sturdy and while the motor looks small, it claims to be 750W and performs like it probably really is about 1 HP. It is set up to offer good power even at slow speeds as well.Speed control is a servo controller - no stepping - just smooth speed control over the full range. They acceleration curve is ramped to provide decent control at low speeds to start and then quickly get to the full speed -Top speed is adjustable from the front panel at any point - default is set to a max of 4500 RPM and it adjusts in 50 RPM steps down to the lowest setting of 200.This is capable of interfacing with a needle position sensor although its not included in this kit.The motor is capable of up to 6000 RPM - and the max speed can be set to any value in an advanced (password protected) parameters menu - the seller responded very quickly when asked for the password and included additional instructions for accessing the advanced setup but for most sewing applications, you won't need to access these. Even at 6000 RPM, the motor runs very smoothly and quietly with very little vibration. There are a lot of individual parameters that can be adjusted in both the standard and advanced menus if necessary to optimize for your use.The speed control lever and linkage has adjustable tension and uses a hall effect sensor for speed control - no contact between the sensor and magnet and nothing electronic to wear out over time (like a potentiometer).The power switch is a separate module on the power cord so it can be mounted in a convenient location.Available in a day for $100 I would consider this an exceptional value -I am using it for a small precision grinder where the original motor and controller was much more expensive but this will work perfectly - higher power, more flexible controller and easily retrofit even though it isn't on a sewing machine.Well made, great value and does everything it says - very pleased with the purchase.