Prerequisites for Defiant Cloaking Mount:
Federation Ship Construction 5 and Ship Construction 5. And you can use this mount on Heavy Escort (240kt) ship only.
Hope this help.
Edit: ooops, too late
Edit2: this is for v1.51 (why not to uprade to 1.6.6?)
[ March 25, 2004, 14:16: Message edited by: aiken ]