Laura rides a 2004 YZ250 and wants to know about the YamaLink amount

I have been looking at the http://www.motorcycleloweringlinks.com/index.php?content=yamaha-lowering-link-yzf and just wondering approximately how much this will actually lower the bike?

Lowers the YZF rear 1.6"/40mm when properly sprung for rider weight + the link's extra leverage.