From inside (document excerpt):
PARTS LIST NO. DATE 530163256 Replaces WEED EATER Rr PARTS LIST PARAMOUNT PARTS LIST POULANR PARTS LIST Note: Illustration may differ from actual model due to design changes R R CHAIN SAW MODEL(s) Poulan 1975 PAGE NO. 2/24/04 530163256 12/20/02 1 WARNING All repairs, adjustments and maintenance not described in the Operator’s Manual must be performed by qualified service personnel. TYPE Kit–Oil Check Valve