The SMOS-CryoSat merged Sea Ice Thickness Level 4 product, in NetCDF format, is based on estimates from both the MIRAS and the SIRAL instruments, with a significant reduction in the relative uncertainty for the thickness of the thin ice. A weekly averaged product is generated every day by the Alfred Wegener Institut (AWI), by merging the weekly AWI CryoSat-2 sea ice product and the daily SMOS sea ice thickness retrieval. All grids are projected onto the 25 km EASE2 Grid, based on a polar aspect spherical Lambert azimuthal equal-area projection. The grid dimension is 5400 x 5400 km, equal to a 432 x 432 grid centered on the geographic Pole. Coverage is limited to the October-April (winter) period for the Northern Hemisphere, due to the melting season, from year 2010 onwards.