Easy to carry;Water resistant;Can read and rewriteEach comes with key fob includedCompatible with 125khz RFID reader to accessNo external power required.It applies to access control, hotel locks, staff attendance and access control school campus and payment control, identification and security , parking entry and payment, social security management, transportation payment, , municipal and ancillary service paymentT5577 chip which compatible with EM4305 chipWeight: 47g (10 pcs)Operation frequency: 125 kHzRead and rewrite key tagsDetection distance: 0-5 cmcolour: random color, ' accept the specified colorMaterial: Plasticsize: 3.5x2.9x0.5cmPackage Contents: 50 * T5577 KeytagsOnly the above package content, other products are not included.Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.