This attenuator is brand new, 2-6A-MFA series from Bird. It is 2 Watt max average power, 500 watt peak, 30db attenuator, and is good from DC to 6 ghz. It is bidirectional with male on one end, and female on the other. You could easily stack these for greater attenuation values.
The data sheet is available on the Bird site- http://www.bird-electronic.com/products/pdfs/2-6a-mfa-xx.pdf