We Claim:

1. A damper (9) for a fitting (4) for movably supporting a pivoting element (3) or a pullout element, in particular for movably supporting a furniture part (3a), a window or a
5 door, relative to a stationary carrier (2), the damper (9) comprising:
 a damper housing (10),
 at least one fluid chamber (25) arranged in the damper housing (10),
 a damping fluid arranged in the fluid chamber (25),
 at least one piston (17) displaceably supported in the fluid chamber (25),
10  at least one, preferably ring-shaped, sealing element (18) having at least a first
section (18a) which bears against or which is configured to bear against an
inner wall (10a) of the fluid chamber (25),
characterized in that that the at least one sealing element (18) includes at least one,
preferably substantially ring-shaped, second section (18b), the second section (18b)
being spaced apart from the inner wall (10a) of the fluid chamber (25) and being
configured to be moved, preferably pivoted, tilted and/or radially widened, above a
predetermined threshold value of a pressure application to the piston (17), relative
to the first section (18a) which bears against or which is configured to bear against
the inner wall (10a) of the fluid chamber (25).
20

2. The damper (9) according to claim 1, wherein at least one overload channel (23) is
provided, the at least one overload channel (23) being preferably arranged in the at
least one piston (17), wherein the at least one overload channel (23), when a
damping stroke is performed below the predetermined threshold value of a pressure
25 application to the piston (17), is covered by the second section (18b) of the at least
one sealing element (18), and is at least partially open above the predetermined
threshold value of a pressure application to the piston (17).

3. The damper (9) according to claim 2, wherein the overload channel (23) includes at
least one passage (23a), preferably a plurality of passages (23a), arranged in the
piston (17), preferably wherein the at least one passage (23a) is arranged on a
peripheral edge of the piston (17).

4. The damper (9) according to one of the claims 1 to 3, wherein the first section (18a)
and the at least one second section (18b) of the sealing element (18) are spaced apart from each other in a longitudinal direction (L) of the damper housing (10),
and/or the first section (18a) and the at least one second section (18b) of the sealing
element (18) are formed together so as to have an integral one-piece configuration.
5 5. The damper (9) according to one of the claims 1 to 4, wherein at least one streaming
channel (27) is provided, the at least one streaming channel (27) being preferably
arranged on the inner wall (10a) of the fluid chamber (25), wherein the damping fluid
streams through the streaming channel (27) when a damping stroke is performed.

6. The damper (9) according to one of the claims 1 to 5, wherein the at least one sealing
element (18) is axially displaceably supported on the at least one piston (17),
preferably in a limited manner.

7. The damper (9) according to one of the claims 1 to 6, wherein at least one return
channel (24) is provided, the at least one return channel (24) being configured to be
opened upon a movement of the piston (17) in a direction opposite the damping
stroke.

8. The damper (9) according to claim 7, wherein
 the at least one sealing element (18) is movable relative to the at least one
piston (17), wherein the at least one sealing element (18) closes the return
channel (24) in a first relative position to the piston (17), and opens the return
channel (24) in a second relative position to the piston (17), and/or
 the return channel (24) includes at least one recess (24a), preferably a plurality
25 of recesses (24a), arranged in the piston (17), wherein it is particularly
preferable that the at least one recess (24a) is arranged on a peripheral edge
of the piston (17), and/or
 the return channel (24) includes an axial gap (34) arranged between the at
least one piston (17) and the at least one sealing element (18), preferably
wherein a size of the axial gap (34) can be varied upon a movement of the
piston (17) in a direction opposite the damping stroke.

9. The damper (9) according to one of the claims 1 to 8, wherein the at least one piston
(17) includes at least one axial channel (36), preferably a plurality of axial channels
(36), for the passage of the damping fluid.

10. The damper (9) according to one of the claims 1 to 9, wherein the at least one piston
(17) includes at least one disc element (35) on which the at least one sealing element
(18) can be supported at least when a damping stroke is performed.