I have a Homelite ST 155 trimmer and I am not sure what part to purchase. I am looking for a bump feeder and was not sure if I should buy the red or black one and should I have to purchase anything else.
It depends..
If it's a right hand thread bolt then Black (part number HL004 or HL007 for the whole spool assembly kit)
If it's a left hand thread then Red (part number HL005 or HL008 for the whole spool assembly)
search ebay for the above part numbers or call ALM Manufacturing 01423 797208 for stockists