  The phase-out of hydro-fluorocarbons, owing to their high Global Warming
Power, affecting the main gas used in Resistive Plate Chambers (RPCs),
tetrafluoroethane C$_2$H$_2$F$_4$, has increased operational difficulties on
existing systems and imposes strong restrictions on its use in new systems.
  This has motivated a new line of R\&D on sealed RPCs: RPCs that do not
require a continuous gas flow for their operation and dispense the use of very
complex and expensive re-circulation and/or recycling gas systems. At the
moment it is not clear whether this solution can cover all fields of
application normally allocated to RPCs, but it seems that it could be
considered as a valid option for low particle flux triggering/tracking of
particles, e.g. in cosmic ray or rare event experiments.
  In this work, we demonstrate the feasibility of a small telescope for
atmospheric muon tracking consisting of four $300$~x~$300$~mm$^2$ sealed RPCs
with gas gap widths of $1$~mm, $1.5$~mm and $2$~mm. The results suggest that it
is possible to operate this type of detectors for extended periods of time
(more than five months) with its main characteristics, efficiency, average
charge and streamer probability, without apparent degradation and similar to a
RPC operated in continuous gas flow.
