  A recent study using {\it Hinode} (SOT/FG) data of a sunspot revealed some
unusually large penumbral jets that often repeatedly occurred at the same
locations in the penumbra, namely at the tail of a penumbral filament or where
the tails of multiple penumbral filaments converged. These locations had
obvious photospheric mixed-polarity magnetic flux in \NaI\ 5896 Stokes-V images
obtained with SOT/FG. Several other recent investigations have found that
extreme ultraviolet (EUV)/X-ray coronal jets in quiet Sun regions (QRs),
coronal holes (CHs) and near active regions (ARs) have obvious mixed-polarity
fluxes at their base, and that magnetic flux cancellation prepares and triggers
a minifilament flux-rope eruption that drives the jet. Typical QR, CH, and AR
coronal jets are up to a hundred times bigger than large penumbral jets, and in
EUV/X-ray images show clear twisting motion in their spires. Here, using IRIS
\MgII\ k 2796 \AA\ SJ images and spectra in the penumbrae of two sunspots we
characterize large penumbral jets. We find redshift and blueshift next to each
other across several large penumbral jets, and interpret these as untwisting of
the magnetic field in the jet spire. Using Hinode/SOT (FG and SP) data, we also
find mixed-polarity magnetic flux at the base of these jets. Because large
penumbral jets have mixed-polarity field at their base and have twisting motion
in their spires, they might be driven the same way as QR, CH and AR coronal
jets.
