Understanding that it's the details that make the difference between good design and exceptional design we created our keyboard series. The RRKB88W features our exclusive Z-lock Foam System that allows you to customize the inner length, width and height of your case ( length adjustable from 51.5" to 58", depth from 10.5" to 21.5", height from 4.5" to 6.75") to accommodate virtually any model of Roland, Yamaha Korg, EMU and other 88 key keyboards. Simply lock or un-lock the layers of Z-Lock Foam to create your perfect custom fit. And for sleek, stealth mobility we equipped each case with our unique low-profile wheels. Upgrade your keyboard not your case.