I was tired of flashing 1 SD card at a time, Etcher supports writing to multiple cards at once, so I found a cost effective dual card reader and got 3 of them, giving 6 concurrent cards!
3x FREEGENE Dual SD card reader (http://a.co/d/1Eqn8FU)
1x FREEGENE 4 Port USB hub (http://a.co/d/1FkaiI8)
4x M3x45mm bolts
8x M3 Washers
4x M3 Lock Nuts