SIM cards are used in GSM phones. SIM cards has size of an ordinary card - full ISO or microchip module - plug-in. GSM phone network in Slovakia is in the hands of two companies: Eurotel Bratislava company and Globtel GSM company. These companies issued few types of SIM cards full ISO, plug-in and some test cards. These cards are very hard to get. I have few full ISO cards for exchange. I also have many SIM cards plug-in without chips. These cards are manufactured by GEMPLUS and SCHLUMBERGER. The information on the quantities of these cards are a business secret in this period.