SpamRATS maintains several IP-based RBLs, each with a different purpose. We use the RATS-Dyna RBL that tracks IP addresses sending too many connections or trying too many invalid users.
It is referred to in our system as dyna.spamrats.com.
How to delist from SpamRATS
RATS-Dyna listings are usually caused by a rDNS/PTR record that looks like a home connection instead of a mail server. If you don't manage your own mail server, contact your ISP or email provider for help.
Otherwise, you can request delisting with a SpamRATS Lookup.