We found this one very useful, portable and relatively reasonable price. There are different models depending on your requirements, but I don't know if they are certified to IEC60891 and IEC60904-5. Please note that when you test PV panels you also need to measure the solar radiation and the cell temperature. Therefore, if you decide to buy a IV tracer, also consider whether you want to buy a complete one with the solar pyranometer and temperature probe all connected to the tester or whether you will measure the solar radiation and cell temperature separately.