DVD Wavelength?

[Programmer]

The company I work for is ready to buy a DVD-R external drive and it's my responsibility to choose the drive. While price-shopping, I found that DVD-R drives are rated by wavelength... some are 635 while others are 650. What's the significance of this? Is one compatible with standard DVD players and the other is not? What about blank media? Do I have to buy blank media specifically for the wavelength? Which would you recommend... if that's a valid question.

Thanks!

[Darkbird]

I think some advertiser is getting their specs mixed up. Happens all the time.

DVD-R writers burn at one of those wavelengths, while settop players use the other wavelength to play back. The wavelengths were chosen by Pioneer for cross-compatability, so I wouldn't worry about it.