Stens 385-154 Bump Feed Trimmer Head Arbor sizes included: 7mm x 1.00 LHM 8mm x 1.25 LHM 8mm x 1.25 LHF 10mm x 1.25 LHF 10mm x 1.00 LHF Recommended for trimmers under 25cc Single spool allows for single or dual line indexing Uses .080", .095" or .105" diameter line Spool holds 20' of .095" diameter line Uses 385-888 Trimmer Head Spool This is a Stens replacement part Part Number 385-154 This is an aftermarket of generic part