  Interplanetary (IP) shocks are fundamental building blocks of the
heliosphere, and the possibility to observe them \emph{in-situ} is crucial to
address important aspects of energy conversion for a variety of astrophysical
systems. Steepened waves known as shocklets are known to be important
structures of planetary bow shocks, but they are very rarely observed related
to IP shocks. We present here the first multi-spacecraft observations of
shocklets observed by upstream of an unusually strong IP shock observed on
November 3rd 2021 by several spacecraft at L1 and near-Earth solar wind. The
same shock was detected also by radially aligned Solar Orbiter at 0.8 AU from
the Sun, but no shocklets were identified from its data, introducing the
possibility to study the environment in which shocklets developed. The Wind
spacecraft has been used to characterise the shocklets, associated with
pre-conditioning of the shock upstream by decelerating incoming plasma in the
shock normal direction. Finally, using the Wind observations together with ACE
and DSCOVR spacecraft at L1, as well as THEMIS B and THEMIS C in the near-Earth
solar wind, the portion of interplanetary space filled with shocklets is
addressed, and a lower limit for its extent is estimated to be of about 110
$R_E$ in the shock normal direction and 25 $R_E$ in the directions transverse
to the shock normal. Using multiple spacecraft also reveals that for this
strong IP shock, shocklets are observed for a large range of local obliquity
estimates (9-64 degrees).
