Polarising filters which take lens caps

[AlexSingleton]

I'm going to be doing some street photography on Saturday and want a 52mm polarising filter that I can discretely attach to my 35mm and 50mm lenses - my 105mm polarising filter and Lee filter kit is a bit cumbersome.

What I really want is a polariser that either comes with a lens cap or, preferably, takes a standard Nikon cap.

I'd get the B+W Kasemann slim, which comes with its own push on cap, but it seems out of stock here in Britain. I like the look of the Heliopan and Hoya HD polarisers, but wonder if anyone knows the situation with caps.

[Riaan van Wyk]

I would think that the caps fit on most of the standard Circular polarisers Alex- but I'm guessing. I have a few Marumi ones in various diameters and the caps fit on those. 

[Dustbak]

My polarizers can take caps when they are 'normal' sized. The 'slim' versions cannot take caps. Not sure if this applies to all polarizers, I use Nikon, B&W & Heliopan.

[kpmedia]

My B+W filters all work with caps. I have full-sized ones, not those "slims".

[Nill Toulme]

The Hoya Pro1 does, or at least it did when I bought mine.

Nill