SIM Application Toolkit. SIM Application Toolkit (commonly referred to as STK) is a standard of the GSM system which enables the Subscriber Identity Module (SIM) to initiate actions which can be used for various value-added services.
Cook them immediately if they have been thawed for no more than three days! Once you cook them they will last at least for another four or five days in the fridge! If nothing else put them in a good shrimp marinade for about one half hour - then SMOKE them over mesquite or hickory wood for one hour. These will be eaten up before five days is over! Good Luck & Bon Aperitif!
If you've bought frozen shrimp in their original packaging, the packaging will often have a Use-by or Best before date on it. That's the vendor's estimate of how long your shrimp will retain their best flavor and quality. Usually it will be 4 to 6 months for uncooked shrimp, or about half that for cooked. You can still eat them after that time -- they'll be safe for as long as they stay properly frozen -- but their texture will suffer, they'll begin to acquire off-flavors from the freezer, and eventually they'll succumb to freezer burn.