Small Romulan reconnaissance craft, one of which carried the defector Admiral Jarok across the Neutral Zone in 2366.
The Romulan Star Empire used small scout ships for reconnaissance near the Neutral Zone in the 24th century. These light craft were no match for a warbird in combat.
In The Defector, a Romulan calling himself Setal fled across the Neutral Zone in a stolen scout ship, pursued by a warbird, and was taken aboard the Enterprise-D. He proved to be Admiral Jarok, who brought warning of a secret Romulan base. The information had been planted, and Tomalak's warbirds sprang a trap, which Picard escaped with the help of hidden Klingon ships.