Talk:Type 4 Passive Sonar/@comment-26473683-20151013001440/@comment-24930367-20151013010202

To OP:

Type 3 Active Sonar at ★+4 is about equal to this one so I don't think it's worth it.

If you somehow have spare Type 93, you could use it to improve Type 4 after you finished with other things, I guess.