... allowed frequency band has to be selected.TAG and RFID reader need to be coordinated to each other.EM4200 ... :30 mmMifare is related to Near Field RFID technology and reading distance.NXP MIFARE Ultralight C HF ... PVC / PET/Fabric/Highlight photo paper.etc. HF(13.56Mhz)Square Size 18*18mm,25*25mm,30*30mm,35* ... 35mm,38*38mm,50*50mm,or in customized.HF(13.56Mhz)RoundDiameter:20mm,25mm,26mm,28mm,30mm,35mm,38mm, ...