Jack and Lamm for Standard Floor LoomIncludes one assembled jack and lammbe sure to choose the correct number! (Lamm bars vary in length.) SFL 4 Now 4 Later requires two each of #1, #2 SFL 8 shaft requires two each of #1, #2, #3, #4 Fits all maple Standard Floor Looms except the original 42" weaving width. Each shaft harness of the loom requires a jack and lamm assembly. If you don't know what jack and lamm numbers you have, measure the entire lamm bar on each jack and lamm: all #1 jack