These MG Electronics Ribbon Tweeters are rated at 120 watts, at 8Ω.  They have never been removed from the original boxes save for the photos included in the listing. 

The exact date of manufacture is unknown, but the best estimate would make these drivers 25 to 30 years old.  

Here are the pertinent specifications:

• Mounting plate measures 4.75" x 4"  (LxW)
• Ribbon opening measures 2" x .5"
• Mounting holes are on 3.125" centers Vertically,  4" Horizontally

These Tweeters were manufactured by MG Electronics, who were (and remain) OEM manufacturers for many brands available through various electronic distributors such as Radio Shack,  MCM and Parts Express.