[Question] Neutral Density Filters(ND)

I'm thinking about buying a ND2 and a ND4 filter to use with a LPM. My question is, is it safe to trust ebay shops for these? I'm not really sure what differentiates lenses so I'm a bad judge for this type of thing.
I'm looking at the following links:
30 mm 30mm Neutral Density ND 2 ND2 Filter - eBay (item 250514557925 end time Apr-13-10 04:23:38 PDT)
Green.L 37mm 37 mm Neutral Density ND 2 ND2 Filter - eBay (item 280297539943 end time Mar-22-10 05:15:52 PDT)

Those are the cheap ones. In his LPM thread, Laserbee also linked to an ebay store selling these filters and that store is linked below:
New 37 ND Neutral Density ND2 ND4 ND8 Filter Set 37mm on eBay.ca (item 370256758724 end time 05-Apr-10 01:18:16 EDT)

The size of the lens doesn't really matter to me, and I'll probably only ever need a ND2 and ND4 filter, so... discuss?

Well... like I said in my PM... reading the HLPM II sales thread.. you
fimd a Post #77 by HIMNL9 has a links to higher quality more linear
reflective ND filter suited for Lasers that is supplied by Newport for
$43.99 plus shipping... here is the chart for the different models...



The eBay ones I linked to we use in the shop... They are photographic
Filters and you will need to test the reduction ratio for the wavelength
of Laser you are metering.


Jerry