SKB 3R4024-18 Custom Foam For 60 Minix Neo Z83-4 Pro Mini PCs Includes: Dual layer design to hold 30 PC's on each layer. Top layer with Rigid acrylic bottom for support. Overview: Polyurethane foam is the most common type of foam used in cases. The foam is soft enough to provide flexibility for items, but also dense enough to provide cushion for even the heaviest of items. Technical: Polyurethane is open cell which means air and water can flow freely throughout the foam. The material weighs about 1.2 - 1.3 lbs per cubic foot. PRODUCT FEATURES: REPLACEMENT FOAM INSERTS BY COBRA FOAM - manufactured locally, specifically for protective cases. TOP QUALITY POLYURETHANE FOAM - The foam is soft enough to provide flexibility for items, but also dense enough to provide cushion for even the heaviest of items. SKB 3i-3614-6 - All inserts are cut to factory specs by computerized CNC (Computer Numerical Control) machines to insure a proper and snug fit. ROUNDED CORNERS FOR A SNUG FIT.