Click to expand Tap to zoom Haltec Mega Bore MB-13 Valve Cap with O-Ring Seal by Haltec Corporation No reviews $29.99 | / SKU HTMB13 1 2 3 4 5 6 7 8 9 10+ Quantity Quantity Add to cart Haltec's MB-13 Mega Bore valve cap is designed to protect the core housing from damage on Mega-Bore valve stems. Each cap includes an internal O-ring seal to help protect dirt and grime from entering the valve stem.