www.parker.com/ipd us CPI /A-LOK Tube Fittings Parker CPI /A-LOK Tube Fittings are ... part number aslisted in this catalog. Size: Tube and pipe thread sizes are designed ... by the number of sixteenths of an inch (1/2" tube 8/16" 8) (1/4" ... pipe thread 4/16" 4). StraightsElbows: Call out largest CPI /A-LOK ... tube end sizefirst followed by the smaller CPI /A-LOK tube end or pipe thread ... size. TeesCrosses: For drop sizeteesfirstsize the run (1 to 2) and ... then branch (3). Example the sizedesignator for a male run tee for 3/8 ... would be 6-4-6. For crossesfirstsize the run (1 to 2) and then the branch ( ... 3 to 4). For tees with all ends the same, use the tube and size before and after ...