I bought the two on the outside(blue and pink) first and my husband and I used them until they actually couldn't be used anymore. They didn't stop burning or anything we just used them as actual tools so much they kinda fell apart.
But they made it through everything. Mine(Blue) made it my entire apprenticeship as a measuring tool, box opener, and pen (1 year 8 months).
My husbands(Pink) though made it as a warehouse tool, breaking down boxes, writing on and sometimes cutting cardboard, I'm p...