The implementation is simple. You can choose a custom name and ringtone for each sim, but no color. You can set a default sim for calls and sms, a sim for data and select 4G sim (Honor 6 plus only). When making a call you have two call buttons with the custom names. When receiving a call, the name of the sim is shown. Yes sorry, I was referring to newer/current models, not the old models. Yes One M7 802W is Full Active, but current models HTC One M8 and E8 models are Dual Standby. The same with Samsung where Note 3 is Full Active, but Note 4 and S5 is Dual Standby only.