Schluter® KERDI-FLEX 10" Movement StripKERDI FLEX is a waterproofing strip with a built in elastomeric center section that accommodates movement at structural joints, expansion joints, and transitions between different substrates. Standard KERDI membrane and KERDI BAND are rigid they'll bridge a seam, but they can't handle substrates that move independently. KERDI FLEX can. The 10" width gives you 5" of bonding area on each side of the movement joint, with the flexible center section