This knife too is used for general purpose marking.
As to the two knives above the Stanley knife, I suspect most viewers will discern at one glance that they are highly sophisticated custom made items carefully crafted for ergonomic comfort using first class rare materials including broken hacksaw blade, scrap mahogany, sisal or similar string soaked in diluted PVA adhesive and carefully wrapped and knotted around the perfectly formed handles. I think there may also have been a little epoxy resin used to fix the carefully shaped and honed blades into the slot in the handles.
I'd be happy to take orders for similar examples of these lovingly crafted artisanal items: £50 each, or discounted to £95 for a matching pair, plus P&P, payable in advance, non-refundable. However, bear in mind that if you order I may not be in the mood to make them, so probably wouldn't, and once your money goes into my bank all entreaties from 'customers' to return their pre-payment will most likely be ignored. Slainte.