This is a simple but effective process of scraping away the black coating within the outlines to reveal the colour layer and should appeal to a wide and range.
I particularly like activities where there is an end product for the child to keep or gift to somebody (especially something practical like a bookmark to encourage reading). This could also hone fine motor skills whilst being great fun.
At the time of review this set had been reduced to £4.99 which is excellent value for money.