The TUF swab cup is a flexible, synthetic rubber cup with spring steel reinforcing wires for heavy loads but is flexible enough for light or medium loads. The TUF swab cup is an all-purpose, synthetic rubber cup containing strong, flexible spring steel reinforcing wires. Technical Parameters: Tubing O.D. LBS./Foot Tubing Min I.D. Nominal Tubing Size Wire Cup 2.375 4.6 1.995 2â?? PW2R 1.935 2.375 4.6 1.995 2â?? PW2R 1.915 2.875 6.4 2.441 2-1/2â?? PW2-1/2R 2.370 2.875 6.4 2.441 2-1/2â?? PW2-1/2U 2.340 2.875 7.9 2.323 2-1/2â?? PW2-1/2HS 2.220 2.875 8.7 2.259 2-1/2â?? PW2.259 2.050 3.50 8.5-10.2 2.992 3-1/2â?? PW3-1/2 2.920 4.50 10.4-12.5 4.090-3.958 4-1/2â?? PW4-1/2C 3.890 5.50 13.5-15.5 5.044-4.950 5-1/2â?? PW5-1/2C 4.920