[Elecraft] OT: Bird watt meter?

[nz7c@cox.net]

Hi folks -
Could someone tell me:
1 - Why are Bird meters so well regarded?
2 - Are they still manufactured?
3 - What is a slug?
4 - Will they measure QRP levels? If so, better than OHR meter?
5 - What would be the recommended slugs, specific meter (if there is more than one model), and accessories for measuring milliwatts up to 100 watts.
6 - What would be a reasonable price range to pay for the above?
7 - What would be the most common problem to look out for when shopping for a used meter?

Thank you - probably should reply direct - but other Elecraft users may be interested in learning from some of the pros :-) Thanks folks.
73/NZ7C