Lower Knife #61398 For Babylock BL402 BL550, Simplicity SL4380 SL4390 Serger
Lower Knife For Domestic Sergers. Part # : 61398 Fits Babylock models : BL402 (Protege), BL550, BL5370, BL5370ED Fits Riccar models : RL739DE, RL749L Serge-Mate models : ST600L Fits Simplicity models : SL4380BH, SL4380ED, SL4390ED, SL4390L