The Cisco VPN 3000 series Concentrators are a family of remote access VPN platforms that incorporate high availability and high performance with some of the best encryption and autherntication security available. 

Models:

VPN 3005 - supports up to 100 users

VPN 3015 - supports up to 100 users - has 4 expansion slots

VPN 3030 - supports up to 1500 users

VPN 3060 - supports up to 5000 users

VPN 3080 - supports up to 10,000 users