(1) High quality and durable (2) With anti-vibration rubber caps 　　 (3) Bearing Weight: 85 - 170kg (4) made of electro-galvanized, metal sheet, with epoxy spray, no rusty . SP430 Suitable for (BTU): 7000-18000 , 20'FT Qty: 7488 sets/20' container SP550B Suitable for (BTU): 24000, 20'FT Qty: 4416 sets/20' container