On the UK website, not sure about US, it is nearly impossible to find a sync module alone, and even when you do the pricing is all messed up, stating £50 on Blink’s web site, but when you click to ‘buy on Amazon’, it says £89.99. That having been said, you seem to be suggesting that you can’t buy a bundle, including a sync module?
If so, this has me confused, because for me, it is all but impossible to find anything other than complete systems, bundled with a sync module, whereas you state none of them do. Can you confirm if you want a sync module alone, or a single camera system?
Whilst we’re on the subject, I’d like to ask @Bob_at_Blink if he knows why the £50 spare sync module, is £89.99 on amazon, when you click the pull through link, which says, “Buy on Amazon”.