Ask HN: How do you send your cold sales emails?

Let's face it, cold sales emails work. I'm currently using mailwizz + powersmtp, warming up with warmupinbox.com and cleaning lists.

The results leave alot to desire. In the past I've used gmail + woodpecker but it doesn't seem to scale well although it gets good open rates.

What scalable methods do you use for sales? (b2b)