Classification for high-pressure hoses and fittings used in hydraulic system piping connections. Hydraulic hoses serve as flow paths for high-pressure hydraulic fluid in hydraulic circuits of press machines, injection molding machines, machine tools, construction machinery, etc. Fittings are used to connect hoses to each other or hoses to equipment, including straight fittings, elbow fittings, tee fittings, couplings, adapters, etc. Pressure resistance performance, size, and materials (stainless steel, carbon steel, etc.) are important selection factors, with products primarily conforming to JIS and ISO standards. Distinguished from main equipment such as hydraulic pumps and cylinders, these are positioned as component groups specialized for piping system construction and maintenance.