The old generation of ELBs, not recommended/available for new applications (useful if you are using EC2 Classic Instances).
performs routing on layer 4 and 7. Despite not having so many features as ALB it has something that is not provided by ALB like
support for EC2 classic
support for TCP and SSL Listeners
support for sticky sessions using application generated cookies
cross-zone load balancing can be disabled
does not support target groups, but rather the target instances can be directly selected.