If you are not sure of the size for your loom, you will need to measure. Determine the distance from the top of the heddle bar on the shaft/harness to the bottom of the bottom bar.
Please note, when buying and installing heddles: on Texsolv heddles, do not remove all the twist-ties until the heddles are on the heddle bars. On wire heddles, do not remove the string until the heddles are installed on the heddle bars. These restraints serve to keep order, and we will not take back un-restrained heddles if you have ordered the wrong size