Bracket for "M" cylinder: A low cost answer to compressed gas cylinder storage where space is at a premium. The 12-gauge steel, PVC coated brackets are tough, durable, and corrosion-resistant. Ideal for use in emergency and rescue vehicles, industrial plants and hospitals. Mount on any surface. All units comply with AMD Standard 003 for oxygen tank retension systems and GSA KKK specification when used as recommended. Comply with OSHA and insurance safety regulations.Model QR-M will retain "M" cylinders with 6-3/4" to 7-3/4" O.D. Patent No. D267,227.