help identifying filters

[jackfrost]

i am about to put on ebay some old stuff that I started learning photography on. most of it was given to me by my mom or my grandma, and I have a couple filters that I'm not sure what they even are. anybody know what these are?

1: Kenko PL Ø49 JAPAN (i assume the Ø49 is 49 mm diam)
2: PRO 49Ø 81B JAPAN
3: Kenko Px2 Ø49 (doubler?)
4: Kenko LBW4 Ø49

I also have a packet of 3 close-up lenses, but they are marked No. 1, No. 2, and No. 4. what do the numbers mean?

thanks!

 

[Dweller]

PL is probably a polarizer.
81B is a warming filter (does it have an orangish tint?)
PX2 "doubles image size"
LBW4 Blue, for correcting color balance in early morning late evening

All of these came from google searches except the a8B. I have one of those.

As for the closeup filters I think the numbers basically indicate strength. 1, 2, 1+2 for 3, 4, 1+4 for 5 etc up to 7 when using all three of them together.