Abstract: In a device for improving the seal between the cuff (3) of a ski boot (1) or an inner (5) and the leg with a band (6) mounted on boot (1) or on inner (5), said band surrounding boot (1) and the leg and being closable beltwise, band (6) has at least one coupling member (13, 14) for optional mounting on cuff (3) or inner (5) of boot (1), said member being connectable with a matching computing member (11, 14) on cuff (3) or inner (5) of boot (1).