Used this for my GK64. Bluetooth connection was quick and easy. I’ve learnt that the adapter doesn’t have its own battery and needs the powerbank as an external battery. Unplugging from and replugging the adapter to the cable takes 1-2 seconds for the Bluetooth connection to be remade, but disconnecting and reconnecting the powerbank and adapter takes longer, about 5s - probably because the adapter needs to turn on again. Definitely recommend this, my keyboard’s now free to move around, not constrained by my computer!
PhanalaxI got mislead by the description of the product on massdrop which mentions that the light indicator would light when battery needs a recharge. Glad I looked through the reviews and saw your comment about needing a power bank.