Class 7
The term class 7 could refer to:

 Class 7 gas giant, a type of planet
 Class 7 vessel, a type of space vessel
 Class 7 warp drive, a type of warp drive

You may also be looking for:
 Type 7 phase discriminator, a type of phase discriminator
 Type 7 shuttlecraft, a type of Federation shuttlecraft
 Level 7 emergency, a type of emergency procedure

Class 07