Insect cells are a good system for expressing recombinant proteins with advanced post-translational modifications. Glycosylations are not identical to those in mammalian cells, but they are very close and often near enough to get functional proteins. The success rate in this system is usually good, but the production process takes longer than other systems, as it is requires to first prepare a baculovirus, transfect Sf9, Sf21 or Hi5 cells with it, and then perform 2 rounds of infection. This system is also known as BEVS, which stands for baculovirus expression vector system. Post-translational modifications (PTM) are usually close to those expressed in mammalian cells.