From the Publisher's web site:

This is the fifth expansion to the popular Beer & Pretzel's Game STARFIGHT. The expansion features four new ships, and new weapon type. This is not a game itself, you need the Starfight base rules in order to use this expansion. This PDF contains:

A rulesheet
Four ship sheets
Four ship screens
Four ship counters
An exclusive proton torpedo die!

The new ships are all equipped with proton torpedoes and cloaking devices!

Expands:

• Starfight