EP Henry 16055937 48" Verti-Block Half Mass Extender Block - This half mass extender block is part of the EP Henry Verti-Block Wall system. Verti-Block is an oversized, hollow pre-cast block that is ideal for a variety of landscaping projects, including gravity walls up to 14' high. Verti-Block can be stained on-site to integrate into existing landscape or hardscape applications.