Abstract: A mobile seat is used in a motorized vehicle to permit a user person seated thereon to displace itself to a desired position and wherein the seat is locked and unlocked at the desired position by the user person in a hands-free mode. The seat comprises a seating member which is displaceably secured between front and rear guide rails. A pivot connection is provided rearwardly of the seating member. A braking element is connected to the seating member for displaceable engagement with the front guide rail by pivoting motion of the seat member about the pivot connection. The braking element is actuable by the position of the user person seated on the seating member whereby to arrest the seat member at a desired position without the use of the user person's hands.