Video at Amazon.com View Surface Pro 3 fits with Type Cover in very good. Is unstable but firmly. In the front pocket, the power supply fits in (the power supply of the Surface Pro 3 is much thinner than that of the Pro 2) is then but close. Alternatively, a USB hub or a flat mouse would fit. Inside the front pocket is still a tab for the pen.
Can not say for sure what kind of material was processed inside, but is very soft.