Reduces amount of caulk you need to fill or seal large openings. Works with virtually every type of caulk & sealant. Made of durable, resilient, moisture repellant poly foam. Just press in place, then caulk on top of it.

• 5/8" x 20'
• Moisture repellent
• Saves expensive caulk while filling large gaps
• Also referred to as backer rod