Portable small 4G device

HI all

i'm just wondering if anyone's come across anything extremely small and portable with 4g and ethernet connection. Basically found myself in a data centre where i need a 4g connection get some kit online (so hence needed an Ethernet port to connect the kit to) s that once kit was online could ge tthe mac address. was a complete ballache, but i've started looking around for somthing i can just carry, grab the sim out of my phone, plug it in and then give the switch an ethernet connection out. Not expecting great speeds or scale able, just to get me out of a fix in the future!