Trigonox® V388 is general purpose methyl ethyl ketone peroxide (MEKP) for the curing of unsaturated polyester resins in the presence of a cobalt accelerator at room and elevated temperatures. The curing system Trigonox® V388/cobalt accelerator is developed for general purpose GRP- and non GRP-applications such as the curing of laminating resins and castings. Practical experience throughout many years has proven that for marine applications a special MEKP with low water content and without polar compounds is demanded in order to prevent from osmosis and other problems. Butanox® M-50 is the MEKP advised for this application. For room temperature application it is necessary to use Trigonox® V388 together with a cobalt accelerator (e.g. Accelerator® NL-49PN).