1223-M300-D is a series 1223 Flex-Tube® U-tube manometer which combines the inherent accuracy of the "U" Tube with the durability of tough, long-lasting plastic construction. The columns are made of 0.375˝ O.D. flexible and shatterproof clear butyrate tubing and are backed by a white scale channel to provide maximum color contrast. This manometer is ideal wherever a portable, direct reading manometer is needed. The Series 1223 Flex-Tube® U-tube manometer used for either portable or stationary use. Safety traps prevent loss of indicating fluid in case of accidental over-pressure. Tubing is permanently bonded to a molded, high impact acrylic plastic top that contains safety traps. Large magnetic clips and clamp bar are provided. Standard type "a" connections include two rapid shut-off type molded nylon tubing connections, two 3-foot lengths of flexible Tygon® plastic tubing, and two 1/8˝ pipe thread to tube adaptors.