Device Studio is designed to enable support for complex devices and can poll multiple OIDs as part of a single custom poller definition. While Universal Device Poller (UDP) is also used for custom SNMP polling, it is generally limited to a single OID per poller. Device Studio is intended for use cases that require combining and correlating multiple OIDs for richer, template-based device monitoring.
Reference:
" Device Studio allows users to create custom device pollers that support multiple OIDs, enabling sophisticated monitoring for non-standard devices. This surpasses the single OID limitation of the classic Universal Device Poller (UDP). "
- (NPM Administrator Guide, Device Studio section)

Comprehensive and Detailed Explanation From Exact Extract:
When you create a flow alert in SolarWinds, the object of the alert (such as a specific interface, node, or application) is chosen from the "Create a Flow Alert" panel. Flow alerts are not based on custom SQL queries, require the NetFlow service to be running, and always have associated trigger actions.
Reference:
NTA Administrator Guide, "Creating Flow Alerts,"
"In the Create a Flow Alert panel, you select the object to be monitored for flow-based alerting."