MikroTik MTAO-LTE-5D-SQ, mANT LTE 5o, 5dBi LTE antenna with 2 x SMA connectors
Been using this for around 8 Months, indoor antennas on TP Link MR600 gave me around 60 Mbps, installed on outside wall and now have +200 Mbps. Walls are 50 cm stone and have steel inside so block a good percentage of 4G signal. I paid 21 Euros for this and 12 Euros for 5 Metre extension cables.
Hope that's useful.