Invisible tack / tack

Cap of Ordinary tacks are designed widely in horizontally to push easily the tack.
Naturally, tack stands on floor as sharp pin-up when it dropped.
and this can be the reason of minor injuries in common life.
"Invisible Tack" has vertically slim cap
This tall and slim cap can prevent injuries when if it dropped on floor.
And show you clear photo or papers contents.
because of slim cap, it almost invisible-slim on wall.
Additional, no more quivering two fingers when you remove the tack from wall.