18' of strong double-sided, low-profile tape for extra support of attaching SunTouch heating mats to the subfloor and hold the mat securely in place. Then you can easily trowel mortar over the top.
Especially helpful for installing mats on concrete slabs or concrete board. You can staple the mat (not the heating wires) directly to plywood floors and may not need tape.
Generally, you need a strip of tape for each of the 2 longest mat edges.
SunTouch does not recommend using other tapes under or on top of SunTouch TapeMats as other tapes (especially duct tape) may compromise the bond of your tile and mortar to the mat and the subfloor.