Commonly requested 5/8” and 13/16” head sets for SAE size flare nuts are now available Most mini-split manufactures refer to metric sizes regarding line sets and flare nut sizes in their literature. However, we have heard that on many occasions, most contractors will purchase US made line-sets with SAE size flare nuts. The two most common sizes appear to be 1/4” and 3/8” line sets, which equates to 5/8” and 13/16” size flare nuts, respectively. The size heads that are missing from our current 60550 torque wrench kit are 5/8” (16mm) and 13/16 (21mm). These heads are now available as a separate kit under part number 60653.