I had a look at the T&C for the trade in (they actually refer to it being for the GW4) as I wanted to trade my old moto 360 gen 2 and keep my original GW as a backup. T&Cs state must be original strap AND charger! It's not at all obvious that's what they want when you're going through the order. I'm hoping this is just part of the generic T&C and they won't actually care. Though it does state that you could be charged if you don't send everything. Best to contact customer service for a definitive answer.