This replacement blade fits snuggly onto the trimmer and printed with PLA and 100% infill it seems to stay alive way longer than the original ones - so far the battery is empty earlier than the blade is failing :-). Would be interesting to see if printed with Nylon gives even better results.
My print time was ~9 minutes and the material cost ~5-6 cents. The original replacement blade was usually around 0.50 € and as stated before, not holding anyhow as long as my PLA print.
https://en.wikipedia.org/wiki/String_trimmer
A string trimmer also called a weed eater, weed whacker, weedwacker, weed whip, line trimmer, brush cutter, whipper snipper (in Australia, Canada, and South Africa) or strimmer (in the UK and Ireland), is a garden tool for cutting grass, small weeds, and groundcover.
The author hasn't provided the model origin yet.