You run wiring through exterior wall insulation and the batts compress around the wires — now you have thermal bypasses that cost you R-value and may not pass the energy code inspector. Air sealing at the wire penetration matters, and doing it right the first time avoids the call back. 3-foot by 5-foot fiberglass insulation batt insulator kit. Five kits per pack — enough to handle the wire runs on a typical residential exterior wall section. The rigid foam panels create a thermal break around the wire where it passes through the batt, preventing compression and maintaining the rated R-value of the surrounding insulation. Standard in the detail work of energy-retrofit contractors and insulation specialists across northeast Nebraska and northwest Iowa — what the crew reaches for when air-sea Stocked at Crofton Lumber and Akron Lumber.